Shaft Seal Assembly

ABSTRACT

A shaft seal assembly comprises a stator configured to engage a housing and a rotor positioned within the stator. The stator may include a main body, a stator inward radial projection extending radially inward from the stator main body, and a collection groove adjacent the stator inward radial projection. The rotor may include a rotor main body and a rotor axial projection extending from the rotor main body. The rotor axial projection may be positioned adjacent a distal end of the stator inward radial projection.

CROSS REFERENCE TO RELATED APPLICATIONS

This patent application claims priority from and is acontinuation-in-part of U.S. patent application Ser. No. 15/134,714filed on Apr. 21, 2016, which application claimed priority fromprovisional U.S. Pat. App. Nos. 62/150,633 filed on Apr. 21, 2015 and62/210,066 filed on Aug. 26, 2015. The present application also claimspriority from provisional U.S. Pat. App. No. 62/416,082 filed on Nov. 1,2016, all of which applications are incorporated by reference herein intheir entireties.

FIELD OF THE INVENTION

The present invention relates to a shaft seal assembly and/or bearingisolator with multiple embodiments. In certain embodiments, the shaftseal assembly may be used as a product seal between a product vessel anda shaft therein.

STATEMENT REGARDING FEDERALLY SPONSORED RESEARCH OR DEVELOPMENT

No federal funds were used to create or develop the invention herein.

REFERENCE TO SEQUENCE LISTING, A TABLE, OR A COMPUTER PROGRAM LISTINGCOMPACT DISK APPENDIX

N/A

BACKGROUND OF THE INVENTION

For years there have been a multitude of attempts and ideas forproviding a satisfactory seal when a rotatable shaft is angularlymisaligned resulting in run out of the shaft. Typically the solutionspresented have failed to provide an adequate seal while allowing for anacceptable amount of shaft misalignment during operation. The problem isespecially acute in product seals where the potential for shaft to boremisalignment may be maximized. A typical solution in the prior art is toincrease the operating clearance between the rotating shaft and sealingmembers to create a “loose” clearance or operating condition. “Loose”running for adjustment or response to operational conditions, especiallymisalignment of the shaft with respect to the stator or stationarymember, however, typically reduces or lowers the efficiency and efficacyof sealing members.

Labyrinth seals, for example, have been in common use for many years forapplication to sealing rotatable shafts. A few of the advantages oflabyrinth seals over contact seals are increased wear resistance,extended operating life and reduced power consumption during use.Labyrinth seals, however, also depend on a close and defined clearancewith the rotatable shaft for proper function. Shaft misalignment is alsoa problem with “contact” seals because the contact between the seal andmisaligned shaft typically results in greater wear. Abrasiveness of theproduct also affects the wear pattern and the useful life of the contactseals.

Prior attempts to use fluid pressure (either vapor or liquid) to sealboth liquid and solid materials in combination with sealing members suchas labyrinth seals or contact seals have not been entirely satisfactorybecause of the “tight” or low clearance necessary to create the requiredpressure differential between the seal and the product on the other sideof the seal (i.e., the tighter the seal, the lower the volume of fluidrequired to maintain the seal against the external pressure ofmaterial.) Another weakness in the prior art is that many product sealsexpose the movable intermeshed sealing faces or surfaces of the productseal to the product resulting in aggressive wear and poor reliability.Furthermore, for certain applications, the product seal may need to beremoved entirely from the shaft seal assembly for cleaning, because ofproduct exposure to the sealing faces or surfaces.

The prior art then has failed to provide a solution that allows both a“tight” running clearance between the seal members and the stationarymember for efficacious sealing and a “loose” running clearance foradjustment or response to operational conditions especially misalignmentof the rotatable shaft with respect to the stator or stationary member.

BRIEF DESCRIPTION OF THE DRAWINGS

The accompanying drawings, which are incorporated in and constitute apart of this specification, illustrate embodiments and together with thedescription, serve to explain the principles of the shoe covering.

FIG. 1 is a perspective exterior view of an illustrative embodiment of ashaft seal assembly.

FIG. 2 is an exterior end view of the embodiment of a shaft sealassembly shown in FIG. 1 with the shaft element aligned.

FIG. 3 is a cross-sectional view of a first embodiment of the shaft sealassembly, as shown in FIG. 2 and mounted to a housing.

FIG. 3A provides a detailed view of a top portion of the firstembodiment of a shaft seal assembly during angular and radial shaftalignment.

FIG. 3B provides a detailed view of a bottom portion of the firstembodiment of a shaft seal assembly during angular and radial shaftalignment.

FIG. 4 is an exterior end view of the first illustrative embodiment of ashaft seal assembly with the shaft misaligned.

FIG. 5 is a cross-sectional view of the first embodiment of a shaft sealassembly as shown in FIG. 3 during both angular and radial misalignmentof the shaft.

FIG. 5A provides a detailed view of a top portion of the firstembodiment of a shaft seal assembly during angular and radial shaftmisalignment.

FIG. 5B provides a detailed view of a top portion of the firstembodiment of a shaft seal assembly during angular and radial shaftmisalignment.

FIG. 6 is a cross-sectional view of a second embodiment of a shaft sealassembly FIG. 7 is a cross-sectional view of a third embodiment of ashaft seal assembly.

FIG. 8 is a perspective view of a fourth embodiment of a shaft sealassembly engaged with a vessel wall.

FIG. 9 is a cross-sectional of view of another embodiment of the shaftseal assembly with the shaft aligned with respect to the housing.

FIG. 9A provides a detailed view of a top portion of the embodiment ofthe shaft seal assembly shown in FIG. 9.

FIG. 9B provides a detailed view of a bottom portion of the embodimentof the shaft seal assembly shown in FIG. 9.

FIG. 10 is a cross-sectional view of another embodiment of the shaftseal assembly with the shaft aligned with respect to the housing.

FIG. 10A provides a detailed view of a top portion of the embodiment ofthe shaft seal assembly shown in FIG. 10.

FIG. 10B provides a detailed view of a bottom portion of the embodimentof the shaft seal assembly shown in FIG. 10.

FIG. 11 is a cross-sectional view of the embodiment shown in FIG. 10with the shaft misaligned with respect to the housing.

FIG. 12 is a cross-sectional view of the embodiment shown in FIG. 9 withthe shaft misaligned with respect to the housing.

FIG. 13 is a cross-sectional view of the embodiment shown in FIG. 9 withthe shaft misaligned with respect to the housing.

FIG. 14 is a cross-sectional view of a third embodiment of the shaftseal assembly.

FIG. 15 is a perspective view of a first embodiment of a multi-shaftseal assembly.

FIG. 16 is a plane vertical view of another embodiment of a shaft sealassembly.

FIG. 17 is an axial, cross-sectional view of the shaft seal assemblyshown in the embodiment in FIG. 16.

FIG. 18 is an axial, cross-sectional view of another embodiment of ashaft seal assembly.

FIG. 18A is an axial, cross-sectional view of a top portion of theembodiment of a shaft seal assembly shown in FIG. 18.

FIG. 19 is a perspective view of a first embodiment of a multi-shaftseal assembly.

FIG. 19A is a perspective view of the embodiment of a multi-shaft sealassembly shown in FIG. 19 with the second seal removed for clarity.

FIG. 19B is a rear perspective view of the embodiment of a multi-shaftseal assembly shown in FIG. 19.

FIG. 20 is a plane vertical view of the embodiment shown in FIG. 19.

FIG. 21 is an axial, cross-sectional view of the embodiment shown inFIG. 19.

FIG. 22A is perspective view of another embodiment of a shaft sealassembly.

FIG. 22B is an axial, cross-sectional view of the embodiment of a shaftseal assembly shown in FIG. 22A.

FIG. 22C is an axial, exploded cross-sectional view of the embodiment ofa shaft seal assembly shown in FIG. 22A.

FIG. 22D is a detailed cross-sectional view of the embodiment of a shaftseal assembly shown in FIGS. 22A-22C wherein the shaft is verticallyoriented.

FIG. 23 is an axial, cross-sectional view of another embodiment of aporous media shaft seal assembly.

FIG. 24 is an axial, cross-sectional view of another embodiment of aporous media shaft seal assembly.

FIG. 25 is an axial, cross-sectional view of another embodiment of aporous media shaft seal assembly.

FIG. 26 is an axial, cross-sectional view of another embodiment of aporous media shaft seal assembly.

FIG. 27A is an axial, cross-sectional view of another embodiment of aporous media shaft seal assembly.

FIG. 27B is an axial, cross-sectional view of a portion of theembodiment of a porous media shaft seal assembly shown in FIG. 27A.

FIG. 27C is an axial, cross-sectional view of another embodiment of aportion of a porous media shaft seal assembly similar to that shown inFIG. 27A.

FIG. 28A is an axial, cross-sectional view showing other aspects of ashaft seal assembly.

FIG. 28B is an axial, cross-sectional view of a top portion of the shaftseal assembly shown in FIG. 28A.

FIG. 28C is an axial, cross-sectional view of a bottom portion of theshaft seal assembly shown in FIG. 28A.

FIG. 28D is a perspective, cross-sectional view of the shaft sealassembly shown in FIGS. 28A-28C.

FIG. 28E is a cross-sectional view of the shaft seal assembly shown inFIGS. 28A-28D wherein the stator and rotor have been separated from oneanother.

FIG. 29 is an axial, cross-sectional view showing alternative aspects ofa shaft seal assembly.

FIG. 30 is an axial, cross-sectional view showing further alternativeaspects of a shaft seal assembly.

DETAILED DESCRIPTION—ELEMENT LISTING (FIGS. 1-12)

Description Element No. Shaft  1 Fixed stator  2 Fixed stator(part-line)  2a Labyrinth seal  3 Radiused face  3a Floating stator  4Fluid return pathway  5 Shaft seal clearance  6 First o-ring  7Anti-rotation pin  8 Vent  9 Anti-rotation groove (floating stator) 10Spherical interface 11 Anti-rotation pin 12 Second o-ring 13 Labyrinthseal pattern grooves 14 First o-ring channel 15 Cavity for anti-rotationdevice (fixed stator) 16 Axial face of labyrinth seal 17 Axial face offloating stator 18 Second o-ring channel 19 First clearance betweenfloating stator/fixed stator 20 Second clearance between floatingstator/fixed stator 21 Throttle groove 22 Labyrinth pattern annulargroove 23 Sleeve 24 Shaft seal assembly 25 Throttle (alignment skate) 26Floating stator annular groove 27 Labyrinth seal passage 28 Floatingstator passage 29 Housing 30 Angle of misalignment 31 Bearings andbearing cavity 32 Mounting bolts 33 Vessel wall 34 Pressure balancedshaft seal assembly 40 Labyrinth seal interior face 42 Floating statorinterior face 44 Pressure balancing annular channel 46 First radialinterface  47a Second radial interface  47b Fixed stator annular groove48 Annular groove radial-interior surface  48a

DETAILED DESCRIPTION

Before the various embodiments of the present invention are explained indetail, it is to be understood that the invention is not limited in itsapplication to the details of construction and the arrangements ofcomponents set forth in the following description or illustrated in thedrawings. The invention is capable of other embodiments and of beingpracticed or of being carried out in various ways. Also, it is to beunderstood that phraseology and terminology used herein with referenceto device or element orientation (such as, for example, terms like“front”, “back”, “up”, “down”, “top”, “bottom”, and the like) are onlyused to simplify description of the present invention, and do not aloneindicate or imply that the device or element referred to must have aparticular orientation. In addition, terms such as “first”, “second”,and “third” are used herein and in the appended claims for purposes ofdescription and are not intended to indicate or imply relativeimportance or significance. Furthermore, any dimensions recited orcalled out herein are for exemplary purposes only and are not meant tolimit the scope of the invention in any way unless so recited in theclaims.

FIGS. 1-5 provide a view of a first embodiment of the shaft sealassembly 25 that allows for sealing various lubricating solutions withinbearing housing 30. FIGS. 6 and 7 provide alternative embodiments of theshaft seal assembly 25 wherein sealing fluids are used. Applicant hereindefines sealing fluids to include both liquids and vapors. Applicantconsiders air, nitrogen, water and steam as well as any other fluidwhich may work with the proposed shaft seal assembly to provide apressurized fluid barrier for any and all embodiments disclosed hereinto be within the purview of the present disclosure. The gas or fluidchosen is based on process suitability with the product to be sealed.

FIG. 1 is a perspective exterior view of the shaft seal assembly 25arranged and engaged with a shaft 1 inserted through the fixed stator 2of shaft seal assembly 25. FIG. 2 is an exterior end view of the shaftseal assembly with shaft 1 aligned within the shaft seal assembly 25.

FIG. 3 is a sectional view of a first embodiment of the shaft sealassembly 25 shown in FIG. 2 illustrating the shaft seal assembly 25 as alabyrinth seal for retaining lubrication solution within the bearingcavity 32 of housing 30. The shaft 1 shown in FIG. 3 is the type whichmay experience radial, angular or axial movement relative to the fixedstator element or portion of the fixed stator 2 during rotation. Thefixed stator portion of the shaft seal assembly 25 may be flange-mountedor press-fit or attached by other means to a housing 30. The inventionwill also function with a rotating housing and stationary shaft. (Notshown) As required by the particular application, the shaft 1 is allowedto move freely in the axial direction in relation to the shaft sealassembly 25.

A labyrinth seal 3 having an interior surface is engaged with shaft 1. Adefined clearance 6 exists between the interior surface of saidlabyrinth seal 3 and the shaft 1. Opposite the interior surface of saidlabyrinth seal 3 is the radiused surface 3 a of said labyrinth seal 3.The radiused surface 3 a of the labyrinth seal 3 and the interior of thefloating stator 4 forms a spherical interface 11. O-ring channels 15 ando-rings 7 are disposed to cooperate with said radiused surface 3 a ofsaid labyrinth seal 3 to seal (or trap) fluid migration through, betweenand along engaged labyrinth seal 3 and floating stator 4 whilemaintaining spherical interface 11 which allows limited relativerotational movement (articulation) between labyrinth seal 3 and floatingstator 4. O-ring channels 15, as shown, are machined into the floatingstator 4 and positioned at the spherical interface 11 with labyrinthseal 3. O-ring channels 15 are annular and continuous in relation tolabyrinth seal 3. The o-ring channel 15 and o-ring 7 may also be placedin the labyrinth seal 3 adjacent the spherical interface 11. O-rings 7should be made of materials that are compatible with both the product tobe sealed and the preferred sealing fluid chosen. O-ring channels 15 ando-rings 7 are one possible combination of sealing means that may be usedwithin the shaft seal assembly 25 as recited in the claims.Strategically placed anti-rotation pin(s) 12 inserted into anti-rotationgrooves 10 limit relative rotational movement between labyrinth seal 3and floating stator 4. A plurality of anti-rotation grooves 10 and pins12 may be placed around the radius of the shaft 1. If the shaft sealassembly 25 is used in combination with a sealing fluid, strategicanti-rotation pins 12 may be removed allowing correspondinganti-rotation grooves 10 to serve as a fluid passage through vent 9 andlubricant return 5. (See FIG. 7) Additionally, the relationship of thediameters of anti-rotation pins 12 and anti-rotation grooves 10 may beselected to allow more or less angular misalignment of the shaft 1. Asmall diameter anti-rotation pin 12 used with a large diameteranti-rotation groove 10 would allow for greater relative movement of thelabyrinth seal 3 in relation to the floating stator 4 in response toangular misalignment of shaft 1. Labyrinth seal 3 is one possibleembodiment of a sealing means that may be used adjacent to the shaft 1within the shaft seal assembly 25 as recited in the claims.

A continuous annular channel is formed within fixed stator 2 and definedby clearance 20 and 21 as allowed between the exterior of said floatingstator 4 and said interior of said fixed stator 2 of shaft seal assembly25. The annular channel of fixed stator 2 is highlighted as A-A′ in FIG.2. The annular channel of the fixed stator has interior surfaces whichare substantially perpendicular to said shaft 1. The exterior surfacesof the floating stator 4, which is substantially encompassed within theannular channel of the fixed stator 2, cooperatively engage with thefirst and second interior perpendicular faces of the fixed stator 2. Aninner annular interface is formed by the first (shaft seal assemblyinboard side) perpendicular annular channel surface of the fixed stator2 engaging with the first (inboard side) perpendicular face of thefloating stator 4. An outer annular interface is formed by the second(shaft seal assembly outboard side) perpendicular annular interiorchannel surface of the fixed stator 2 engaging with the second (outboardside) perpendicular face of the floating stator 4. O-ring channels 19and o-rings 13 disposed therein cooperate with the surfaces of floatingstator 4 which are in perpendicular to relation to shaft 1 to seal (ortrap) fluid migration between and along engaged floating stator 4 whileallowing limited relative rotational movement between floating stator 4and fixed stator 2. Floating stator 4 and fixed stator 2 are onepossible embodiment of cooperatively engaged sealing means that may beused in combination with labyrinth seal 3 within the shaft seal assembly25 as recited in the claims.

O-ring channels 19 are annular and continuous in relation to shaft 1.The o-ring channels 19 and o-rings 13 may be placed in the body of thefloating stator 4 instead of the fixed stator 2 (not shown) but must beplaced in similar proximal relation. O-rings 13 should be made ofmaterials that are compatible with both the product to be sealed and thepreferred sealing fluid chosen. O-ring channels 19 and o-rings 13 areone possible combination of sealing means that may be used within theshaft seal assembly 25 as recited in the claims.

Strategically placed anti-rotation pin(s) 8 inserted into anti-rotationgroove(s) 16 limit both relative radial and rotational movement betweenfloating stator 4 and interior side of fixed stator 2. A plurality ofanti-rotation grooves 16 and pins 8 may be placed around the radius ofthe shaft 1. The relationship of the diameters of anti-rotation pins 8and anti-rotation grooves 16 may also be selected to allow more or lessangular misalignment of the shaft. A small diameter anti-rotation pin 8and large diameter fixed stator anti-rotation groove allow for greaterrelative movement of the labyrinth seal 3 in response to angularmisalignment of shaft 1.

The labyrinth pattern seal grooves 14 may be pressure equalized byventing through one or more vents 9. If so desired, the vents may besupplied with a pressurized sealing fluid to over-pressurize thelabyrinth area 14 and shaft seal clearance 6 to increase the efficacy ofshaft seal assembly 25. A spherical interface 11 between the labyrinthseal 3 and the floating stator 4 allow for angular misalignment betweenthe shaft 1 and fixed stator 2. O-ring channels 19 are annular with theshaft 1 and, as shown, are machined into the fixed stator 2 andpositioned at the interface between the fixed stator 2 and floatingstator 4. O-ring channel 19 may also be placed in the floating stator 4for sealing contact with the fixed stator 2.

FIG. 3A illustrates seal-shaft integrity during angular and radial shaftalignment. This view highlights the alignment of the axial face 17 ofthe labyrinth seal 3 and the axial face 18 of the floating stator 4.Particular focus is drawn to the alignment of the axial faces 17 and 18at the spherical interface 11 between the floating stator 4 andlabyrinth 3. FIG. 3B illustrates the shaft-seal integrity during angularand radial shaft alignment at the surface opposite that shown in FIG.3A. This view highlights the alignment of the axial faces 17 and 18 oflabyrinth seal 3 and floating stator 4, respectively, for the oppositeportion of the shaft seal assembly 25 as shown in FIG. 3A. Thosepracticed in the arts will appreciate that because the shaft 1 and shaftseal assembly 25 are of a circular shape and nature, the surfaces areshown 360 degrees around shaft 1. Again, particular focus is drawn tothe alignment of the axial faces 17 and 18 at the spherical interface 11between the labyrinth seal 3 and floating stator 4. FIGS. 3A and 3B alsoillustrate the first defined clearance 20 between the floating stator 4and the fixed stator 2 and the second defined clearance 21 between thefloating stator 4 and fixed stator 2 and opposite the first definedclearance 20.

In FIGS. 2, 3, 3A and 3B, the shaft 1 is not experiencing radial,angular or axial movement and the width of the defined clearances 20 and21, which are substantially equal, indicate little movement ormisalignment upon the floating stator 4.

FIG. 4 is an exterior end view of the shaft seal assembly 25 with therotatable shaft 1 misaligned therein. FIG. 5 is a sectional view of thefirst embodiment of the shaft seal assembly 25 as shown in FIG. 3 withboth angular and radial misalignment of the shaft 1 applied. The shaft 1as shown in FIG. 5 is also of the type which may experience radial,angular or axial movement relative to the fixed stator 2 portion of theshaft seal assembly 25.

As shown at FIG. 5, the defined radial clearance 6 of labyrinth seal 3with shaft 1 has been maintained even though the angle of shaftmisalignment 31 has changed. The shaft 1 is still allowed to move freelyin the axial direction even though the angle of shaft misalignment 31has changed. The arrangement of the shaft seal assembly 25 allows thelabyrinth seal 3 to move with the floating stator 4 upon introduction ofradial movement of said shaft 1. The labyrinth seal 3 and floatingstator 4 are secured together by one or more compressed o-rings 7.Rotation of the labyrinth seal 3 within the floating stator 4 isprevented by anti-rotation means which may include a screws, pins orsimilar devices 12 to inhibit rotation. Rotation of the labyrinth seal 3and floating stator 4 assembly within the fixed stator 2 is prevented byanti-rotation pins 8. The pins as shown in FIGS. 3, 3A, 3B, 5, 6 and 7are one means of preventing rotation of the labyrinth seal 3 andfloating stator 4, as recited in the claims. Lubricant or other media tobe sealed by the labyrinth seal 3 may be collected and drained through aseries of one or more optional drains or lubricant return pathways 5.The labyrinth seal 3 may be pressure equalized by venting through one ormore vents 9. If so desired, the vents 9 may be supplied withpressurized air or other gas or fluid media to over-pressurize thelabyrinth seal 3 to increase seal efficacy. The combination of closetolerances between the cooperatively engaged mechanical portions of theshaft seal assembly 25 and pressurized sealing fluid inhibit product andcontaminate contact with the internals of the shaft seal assembly 25.The spherical interface 11 between the labyrinth seal 3 and the floatingstator 4 allow for angular misalignment between the shaft 1 and fixedstator 2. O-ring channel 19 and o-ring 13 disposed therein cooperatewith the opposing faces of the floating stator 4, which aresubstantially in perpendicular relation to shaft 1, to seal (or trap)fluid migration between and along engaged floating stator 4 whileallowing limited relative radial (vertical) movement between stator 4and fixed stator 2.

FIG. 5A illustrates seal-shaft integrity allowed by the shaft sealassembly 25 during angular and radial shaft misalignment. This viewhighlights the offset or articulation of the axial faces 17 of thelabyrinth seal in relation the axial faces 18 of the floating stator 4for a first portion of the shaft seal assembly 25. Particular focus isdrawn to the offset of the axial faces 17 and 18 at the sphericalinterface 11 between labyrinth seal 3 and floating stator 4.

FIG. 5B illustrates seal-shaft integrity for a second surface, oppositethe first surface shown in FIG. 5A, during angular and radial shaftmisalignment. This view highlights that during misalignment of shaft 1,axial faces 17 and 18, of the labyrinth seal 3 and floating stator 4,respectively, are not aligned but instead move (articulate) in relationto each other. The shaft to seal clearance 6 is maintained in responseto the shaft misalignment and the overall seal integrity is notcompromised because the seal integrity of the floating stator 4 to fixedstator 2 and the floating stator 4 to labyrinth seal 3 are maintainedduring shaft misalignment. Those practiced in the arts will appreciatethat because the shaft 1 and shaft seal assembly 25 are of a circularshape and nature, the surfaces are shown 360 degrees around shaft 1.

FIGS. 5A and 5B also illustrate the first clearance or gap 20 betweenthe floating stator 4 and the fixed stator 2 and the second clearance orgap 21 between the floating stator 4 and fixed stator 2 and opposite thefirst clearance or gap 20.

In FIGS. 4, 5, 5A and 5B, the shaft 1 is experiencing radial, angular oraxial movement during rotation of the shaft 1 and the width of the gapsor clearances 20 and 21, have changed in response to said radial,angular or axial movement. (Compare to FIGS. 3, 3A and 3B.) The changein width of clearance 20 and 21 indicate the floating stator 4 has movedin response to the movement or angular misalignment of shaft 1. Theshaft seal assembly 25 allows articulation between axial faces 17 and18, maintenance of spherical interface 11 and radial movement at firstand second clearance, 20 and 21, respectively, while maintaining shaftseal clearance 6.

FIG. 6 is a sectional view of a second embodiment of the shaft sealassembly 25 as shown in FIG. 2 for over-pressurization with alternativelabyrinth seal pattern grooves 14. In this figure the labyrinth sealpattern grooves 14 are composed of a friction reducing substance such aspolytetrafluoroethylene (PTFE) that forms a close clearance to the shaft1. PTFE is also sometimes referred to as Teflon® which is manufacturedand marketed by Dupont. PTFE is a plastic with high chemical resistance,low and high temperature capability, resistance to weathering, lowfriction, electrical and thermal insulation, and “slipperiness.” The“slipperiness” of the material may also be defined as lubricous oradding a lubricous type quality to the material. Carbon or othermaterials may be substituted for PTFE to provide the necessary sealingqualities and lubricous qualities for labyrinth seal pattern grooves 14.

Pressurized sealing fluids are supplied to over-pressurize thelubricious labyrinth pattern 26 as shown in FIG. 6. The pressurizedsealing fluids make their way into the annular groove 23 of the throttle26 through one or more inlets. Throttle 26 is also referred to as “analignment skate” by those practiced in the arts. Throttle 26 allows thelabyrinth seal 3 to respond to movement of the shaft caused by themisalignment of the shaft 1. The pressurized sealing fluid escapes pastthe close clearance formed between the shaft 1 and labyrinth seal 3having throttle 26. The close proximity of the throttle 26 to the shaft1 also creates resistance to the sealing fluid flow over the shaft 1 andcauses pressure to build-up inside the annular groove 23. Floatingannular groove 27 in cooperation and connection with annular groove 23also provides an outlet for excess sealing fluid to be “bled” out ofshaft seal assembly 25 for pressure equalization or to maintain acontinuous fluid purge on the shaft sealing assembly 25 duringoperation. An advantage afforded by this aspect of the shaft sealingassembly 25 is its application wherein “clean-in place” product sealdecontamination procedures are preferred or required. Examples wouldinclude food grade applications.

FIG. 7 illustrates shaft seal assembly 25 with the anti-rotation pin 12removed to improve visualization of the inlets. These would typicallyexist, but are not limited to, a series of ports, inlets or passagesabout the circumference of the shaft seal assembly 25. FIG. 7 also showsthe shape and pattern of the labyrinth seal 3 may be varied. The shapeof throttles 26 may also be varied as shown by the square profile shownat throttle groove 22 in addition to the circular-type 26. Also notethat where direct contact with the shaft 1 is not desired, the shaftseal assembly 25 be used in combination with a separate sleeve 24 thatwould be attached by varied means to the shaft 1.

FIG. 8 shows that another embodiment of the present disclosure whereinthe shaft seal assembly 25 has been affixed to a vessel wall 34. Theshaft seal assembly 25 may be affixed to vessel wall 34 throughsecurement means such as mounting bolts 33 to ensure improved sealingwherein shaft 1 is subjected to angular misalignment. The mounting bolts33 and slots (not numbered) through the shaft seal assembly 25 exteriorare one means of mounting the shaft seal assembly 25, as recited in theclaims.

In certain applications, especially those wherein the process side ofshaft seal assembly 25 (generally the area to the left of the shaft sealassembly 25 as shown in FIGS. 3-3B and 5-7) is at an increased pressure,it is desirable for the shaft seal assembly 25 to be configured tobalance the pressure experienced by the shaft seal assembly 25 in theaxial direction. A pressure balanced shaft seal assembly 40 thatbalances the pressure (in the axial direction) the product applies tothe labyrinth seal interior face 42 and floating stator interior face 44is shown in FIGS. 9-12.

In the first embodiment of the pressure balanced shaft seal assembly asshown in FIGS. 9-10B, the shaft sealing member (i.e., the labyrinth seal3 in combination with the floating stator 4) includes a pressurebalancing annular channel 46. Save for the pressure balancing annularchannel 46, the pressure balanced shaft seal assembly 40 operates in thesame manner as the shaft seal assembly 25 shown in FIGS. 1-8 anddescribed in detail above. That is, the floating stator 4 is positionedin the fixed stator annular groove 48. The first clearance betweenfloating stator/fixed stator 20, which in the embodiments picturedherein is between the floating stator radial-exterior surface 45 and theannular groove radial-interior surface 48 a (shown in FIGS. 9A and 9B),accounts at least for radial perturbations of the shaft 1. The sphericalinterface 11 between the floating stator 4 and the labyrinth seal 3accounts at least for angular perturbations of the shaft 1.

The pressure balancing annular channel 46 is formed in the floatingstator 4 adjacent the first radial interface 47 a between the floatingstator 4 and the fixed stator 2, as shown in FIGS. 9-10 for the firstembodiment. As shown in the various embodiments pictured herein, thefirst radial interface 47 a between the floating stator 4 and the fixedstator 2 is adjacent the portion of the fixed stator 2 fashioned withthe cavity for anti-rotation device 16. That is, the axial face of thefloating stator 4 that is positioned within the fixed stator 2 andfurthest from the process side of the pressure balanced shaft sealassembly 40. A second radial interface 47 b between the floating stator4 and fixed stator 2, which is substantially parallel to the firstradial interface 47 a, is positioned closer to the process side of thepressure balanced shaft seal assembly 40 as compared to the first radialinterface 47 a.

In many applications the optimal radial dimension of the pressurebalancing annular channel 46 will be the substantially similar to theradial dimension of the floating stator interior face 44 so that thearea of the floating stator 4 acted upon by the product and the area ofthe floating stator 4 acted upon by the sealing fluid have equal surfaceareas. In such a configuration, the axial forces will balance if theproduct and the sealing fluid are pressurized to approximately the samevalue. Accordingly, the optimal radial dimension of the pressurebalancing annular channel 46 will depend on the design characteristicsof the entire system, and the radial dimension of the pressure balancingannular channel 46 may be any suitable amount for a particularapplication, whether greater or less than the radial dimension of thefloating stator interior face 44. The axial dimension of the pressurebalancing annular channel 46 will also vary depending on the designcharacteristics of the entire system, including but not limited to thespecific sealing fluid that is used, the product pressure, and thepressure of the sealing fluid. In some applications the optimal axialdimension of the pressure balancing annular channel 46 will be 0.005 ofan inch, but may be greater in other embodiments and less in still otherembodiments.

The pressure balancing annular channel 46 allows sealing fluidintroduced into the first clearance between floating stator/fixed stator20 (from where the sealing fluid may enter the pressure balancingannular channel 46) to act upon the floating stator in an axialdirection. Typically, the process side of the pressure balanced shaftseal assembly 40 (generally the area to the left of the pressurebalanced shaft seal assembly 40 as shown in FIGS. 9-12) experiencesforces from the process fluid acting upon the labyrinth seal interiorface 42 and floating stator interior face 44. These forces are mostoften due to the pressure generated by the rotating equipment to whichthe shaft 1 is coupled. For example, if the shaft 1 is coupled to afluid pump generating seventy pounds per square inch (psi) of headpressure, the process side of the pressure balanced shaft seal assembly40 will be pressurized to approximately seventy psi. This pressurizedfluid will act upon the labyrinth seal interior face 42 and floatingstator interior face 44, and consequently urge the labyrinth seal 3 andfloating stator 4 in the axial direction away from the process side ofthe pressure balancing shaft seal assembly 40 (i.e., generally to theright side of the drawing as depicted in FIGS. 9-12). By contrast,sealing fluid located in the pressure balancing annular channel 46 willurge the labyrinth seal 3 and floating stator 4 in the axial directiontoward the process side of the pressure balancing shaft seal assembly40, which may substantially cancel the axial force the product exertsupon the pressure balancing shaft seal assembly 40, depending on thedesign of the sealing fluid system.

FIGS. 11 and 12 show a second and third embodiment of the pressurebalanced shaft seal assembly 40. The second and third embodiments of thepressure balanced shaft seal assembly 40 generally correspond to thesecond and third embodiments of the shaft seal assembly 25 as shown inFIGS. 7 and 8 and described in detail above. However, as with the firstembodiment of the pressure balanced shaft seal assembly 40 as shown inFIGS. 9-10B, the second and third embodiments include a pressurebalancing annular channel 46.

The various embodiments of the pressure balanced shaft seal assembly 40pictured and described herein are formed with a fixed stator 2 andfloating stator 4 that are comprised of two distinct portions. Theseembodiments facilitate assembly of the pressure balanced shaft sealassembly 40 since in the embodiments pictured herein the majority of thefloating stator 4 is positioned within the fixed stator 2. Wheninstalling a pressure balanced shaft seal assembly 40 according to thefirst embodiment (as pictured in FIGS. 9-10B), the first portion offixed stator 2 (i.e., the portion adjacent the process side of thepressure balanced shaft seal assembly 40) would be affixed to a housing30. Next, the floating stator 4 and labyrinth seal 3 may be positionedas one assembled piece (wherein the components forming the sphericalinterface 11 have been preassembled) between the shaft 1 and the firstportion of the fixed stator 2. The placement of the floating stator 4and labyrinth seal 3 within the fixed stator 3 forms the second axialinterface 47 b between the fixed stator 2 and floating stator 4.Finally, the second portion of the fixed stator 2 (i.e., the portionfurthest from the process side of the pressure balanced shaft sealassembly 40) may be positioned adjacent to and affixed to the firstportion of the fixed stator 2. The positioning of the second portion ofthe fixed stator 2 subsequently forms the first radial interface 47 abetween the fixed stator 2 and floating stator 4.

Alternatively, the floating stator 4 and labyrinth seal 3 may beseparately positioned within the fixed stator annular groove 48. Forexample, after the first portion of the fixed stator 2 has been affixedto the housing 30, the first portion of the floating stator 4 may bepositioned within the fixed stator annular groove 48. The placement ofthe first portion of the floating stator 4 within the fixed statorannular groove 48 forms the second axial interface 47 b between thefixed stator 2 and floating stator 4. Next, the labyrinth seal 3 may bepositioned adjacent the shaft 3, the placement of which forms a portionof the spherical interface 11 between the floating stator 4 andlabyrinth seal 3. Next, the second portion of the floating stator 4 maybe positioned adjacent the first portion of the floating stator 4 andaffixed thereto with a plurality of anti-rotation pins 8, whichcompletes the spherical interface 11 between the floating stator 4 andlabyrinth seal 3. Finally, the second portion of the fixed stator 2 isaffixed to the first portion of the fixed stator 2 with a plurality ofbolts or rivets, the placement of which forms the first axial interface47 a between the floating stator 4 and fixed stator 2. Any suitablesecuring members known to those skilled in the art may be used to affixthe first and second portions of the floating stator 4 to one another orto affix the first and second portions of the fixed stator 2 to oneanother.

Although the embodiments pictured herein are directed to pressurebalanced shaft seal assemblies 40 wherein the fixed stator 2 andfloating stator 4 are comprised of two separate portions, in otherembodiments not pictured herein, the fixed stator 2 and/or floatingstator 4 are formed of one integral member.

Element Listing (FIGS. 13-22 d)

Description Element No. Shaft  10 Bearing isolator  18 Housing  19 Rotor 20 Stator 30, 31a Fixed stator  31 Passage 40, 40a Spherical surface50, 51  Clearance  52 Frictional seal  60 Flange unit  61a Center point 80 Conduit  99 Fluid 100 Pin 101 Annular recess 102 Shaft seal assembly200 Multi-shaft seal assembly 202 Fastener 204 Aperture 206 Fixed stator210 Main body 211 Face plate 212 Pin recess  212a Inlet 214 Annularrecess 216 Sealing member 218 Floating stator 220 Radial exteriorsurface 222 Pin 224 First radial passage 226 Concave surface 228 Rotor230 Roller cavity 232 Cavity wall 233 Roller 234 Second radial passage236 Convex surface 238 First seal 240 Collar 241 Collar lip  241a Collarcutaway 242 Second seal 250 Cutaway 251 Shaft seal assembly 300 O-ringchannel 302 O-ring 303 Unitizing ring 304 Slip ring 305 Firstcooperating cavity  306a Second cooperating cavity  306b Axial passage307 Radial passage 308 Stator 310 Stator body 311 Shoulder 312 Radialbore 313 Axial projection 314 Radial projection 315 Axial channel 316Radial channel 317 Unitizing ring channel 318 Rotor 320 Rotor body 321Rotor axial projection 324 Rotor radial projection 325 Rotor axialchannel 326 Rotor radial channel 327 Rotor unitizing ring channel 328

FIG. 13 shows another embodiment of a bearing isolator 18 mounted on ashaft 10. The shaft 10 extends through the bearing isolator 18 and thehousing 19. A source of gas or fluid, 100 which may include water orlubricant, may also be in communication with the bearing isolator 18 viaconduit 99. The rotor 20 is affixed to the shaft 10 by means by africtional seal 60, which may be configured as one or more o-rings. Therotor 20 follows the rotational movement of the shaft 10 because of thefrictional engagement of the seals 60. The passages 40 and 40 a are asshown but will not be described in detail here because such descriptionis already understood by those skilled in the art.

A pair of corresponding spherical surfaces 50 and 51 may be used tocreate a self-aligning radial clearance 52 between the rotor 20 and thestator 30 prior to, during, and after use. This clearance 52 may bemaintained at a constant value even as the shaft 10 becomes misalignedduring use. Various amounts and direction of misalignment between thecenterline of the shaft 10 and the housing 19 are illustrated in FIGS.15-17. An annular recess 102 between the stator 30 and fixed stator 31allows the bearing isolator 18 to accommodate a predetermined amount ofradial shaft displacement.

In the embodiments shown herein, the spherical surfaces 50, 51 have acenter point identical from the axial faces of both the rotor and stator20, 30, respectively. However, the spherical surfaces 50, 51 may beradially, and/or as shown, vertically spaced apart. These sphericalsurfaces 50, 51 may move radially in response to and/or in connectionwith and/or in concert with the radially positioning of other componentsof the bearing isolator 18. Typically, if the shaft 10 becomesmisaligned with respect to the housing 19, the rotor 20 willconsequently become misaligned with respect thereto, and then thespherical surfaces 50, 51 and/or the stator 30 moving radially withinthe annular recess of the fixed stator 31 may compensate for themisalignment.

FIGS. 15 and 17 illustrate that in one embodiment of the bearingisolator 18, the rotor 20 may move with respect to the stator 30, 31 asshaft 10 is misaligned with respect to housing 19 through theinteraction between spherical surfaces 50, 51 so as to ensure thedistances between the center points of the rotor 20 and stator 30 and afixed point on the housing 19 are constant.

In the embodiment of the bearing isolator 18 shown in FIGS. 14 & 15, thespherical surfaces 50, 51 may be positioned on a fixed stator 31 andstator 31 a rather than on the rotor 20 and stator 30. Still referringto FIGS. 14 & 15, this design allows the rotor 20 and stator 31 a tomove with respect to the fixed stator 31, flange unit 61 a, and housing19. The rotor 20, stator 31 a, and fixed stator 31 may move radiallywith respect to the flange unit 61 a (and consequently with respect tothe housing 19) as best shown in FIG. 15. In this embodiment of thebearing isolator 18 there is a very minimal amount of relative rotationbetween the spherical surfaces 50, 51.

The embodiment of the bearing isolator 18 shown in FIGS. 14 & 15 mayprovide for controlled radial movement of the fixed stator 31, stator 31a, and rotor 20 with respect to flange unit 61 a, which flange unit 61 amay be securely mounted to a housing 19. Rotational movement of thefixed stator 30 with respect to the flange unit 61 a may be prevented byanti-rotational pins 101. The fixed stator 31 may be frictionallysecured to the flange unit 61 a using a frictional seal 61, which may bemade of any material with sufficient elasticity and frictionalcharacteristics to hold the fixed stator 31 in a fixed radial positionwith respect to the flange unit 61 a but still be responsive to theradial forces when the shaft 10 is misaligned. Changes to the radialposition of the fixed stator 31, stator 31 a, and rotor 20 and theresulting positions thereof (as well as the resulting position of theinterface between the fixed stator 31 and stator 31 a) occurs until theradial force is fully accommodated or unit the maximum radialdisplacement of the bearing isolator 18 is reached.

In operation, the rotor 20 may be moved radially as shaft 10 ismisaligned with respect to the housing 19. Radial movement of thespherical surfaces 50, 51 between the stator 31 a and fixed stator mayresult from this pressure. FIG. 3 shows the resultant radial movement ofcenter point 80 as the shaft 10 is misaligned. During normal operation,the shaft 10 is typically horizontal with respect to the orientationshown in FIG. 3, as represented by line A. As the shaft 10 becomesmisaligned in a manner represented by line B, the center point 80 maymove to a point along line A″. As the shaft 10 becomes misaligned in amanner represented by line B′, the center point 80 may move to a pointalong line A′. However, in other shaft 10 misalignments, the radialpositions of the rotor 20, stator 30, and/or fixed stator 31 may beconstant and the spherical surfaces 50, 51 may compensate for the shaftmisalignment. From the preceding description it will be apparent thatthe bearing isolator 18 provides a constant seal around the shaft 10because the distance between the spherical surfaces 50, 51 is maintainedas a constant regardless of shaft 10 misalignment of a normal or designnature.

The physical dimensions of the spherical surfaces 50 and 51 may vary inlinear value and in distance from the center point 80, depending on thespecific application of the bearing isolator. These variations will beutilized to accommodate different sizes of shafts and seals anddifferent amounts of misalignment.

Axial Displacement Shaft Seal Assembly

Another embodiment of a shaft seal assembly 200 is shown in FIGS. 18 &18A. This embodiment is similar to the embodiment of the bearingisolator 18 described above and shown in FIGS. 13, 16, & 17. The shaftseal assembly 200 may include a fixed stator 210, floating stator 220,and a rotor 230, as shown. In the pictured embodiment, the rotor 230typically rotates with the shaft 10 while the fixed stator 210 andstator 220 do not. Accordingly, a rotational interface may exist betweena concave surface 228 of the floating stator 220 and a convex surface238 of the rotor 230. In other embodiments of the shaft seal assembly200 not pictured herein, but which embodiments are a corollary to theembodiment of the bearing isolator 18 shown in FIGS. 14 & 15, thefloating stator 220 may be configured with a convex surface thatcorresponds to a concave surface of the fixed stator. In such anembodiment, the rotational interface may be located at a position otherthan the interface between the concave and convex surfaces.

The embodiment of the shaft seal assembly 200 shown in FIGS. 18 & 18Aincludes a fixed stator 210 that may be securely mounted to a housing(not shown in FIGS. 18 & 18A) my any suitable methods and/or structure.The fixed stator 210 may include a main body 211 and a face plate 212that may be secured to one another. It is contemplated that a fixedstator 210 formed with a main body 211 and face plate 212 may facilitateease of installation of the shaft seal assembly 200 in certainapplications. In such applications, the main body 211 may be affixed tothe housing, the rotor 230 and floating stator 220 may be positionedappropriately, and then the face plate 212 may be secured to the mainbody 211.

The fixed stator 210 may be formed with an annular recess 216 into whicha portion of the floating stator 220 and/or rotor 230 may be positioned.A predetermined clearance between the radial exterior surface 222 of thefloating stator 220 and the interior surface of the annular recess 216may be selected to allow for relative radial movement between the fixedstator 210 and floating stator 220. At least one pin 224 may be affixedto the floating stator 220, and a portion of the pin 224 may extend intoa pin recess 212 a formed in the face plate 212 so as to prevent thefloating stator 220 from rotating with the rotor 230. The axialinterfaces between the floating stator 220 and fixed stator 210 may besealed with sealing members 218, which sealing members may be configuredas o-rings.

The floating stator 220 may also be formed with a concave surface 228 ina radial interior portion thereof. This concave surface 228 may form asemi-spherical interface with a corresponding convex surface 238 formedin the radial exterior portion of the rotor 230. Accordingly, the shaftseal assembly 200 shown in FIGS. 18 & 18A accommodates shaft 10misalignment and radial movement in an identical and/or similar mannerto that previously described for the bearing isolators 18.

The shaft seal assembly 200 may be configured to accommodate for axialmovement of the shaft 10. In the pictured embodiment this isaccomplished by forming at least one roller cavity 232 in the rotor 230adjacent the shaft 10. The illustrative embodiment includes two rollercavities 232 bound by a cavity wall 233 on either end thereof. At leastone roller 234 may be positioned in each roller cavity 232. Axialmovement of the shaft 10 may be accommodated by a roller 234 rollingalong the surface of the shaft 10 and within the roller cavity 232. Theillustrative embodiment includes two roller cavities 232 with one roller234 in each roller cavity 232, but the shaft seal assembly 200 is in noway limited by the number of roller cavities 232 and/or rollers 234associated therewith. The roller(s) 234 may be constructed of anysuitable material for the specific application of the shaft sealassembly 200. It is contemplated that an elastomeric material (e.g.,rubber, silicon rubber, other polymers) will be especially suitable formany applications.

The illustrative embodiment of the shaft seal assembly 200 also includesvarious fluid conduits for applying a sealing fluid to the shaft sealassembly 200. The fixed stator 210 is formed with an inlet 214 forintroduction of a sealing fluid to the shaft seal assembly 200. Theinlet 214 may be in fluid communication with one or more first radialpassages 226 in the floating stator 220, which first radial passages 226may in turn be in fluid communication with one or more second radialpassages 236 in the rotor 230. The roller(s) 234, roller cavity(ies)232, and cavity wall(s) 233 may be configured so that the sealing fluidintroduced to the inlet 214 exits the shaft seal assembly 200 from anarea between the rotor 230 and shaft 10 at a predetermined rate for agiven set of operation parameters (e.g., sealing fluid viscosity andpressure, shaft 10 rpm, etc.). The illustrative embodiment of the shaftseal assembly 200 may be formed with eight first radial passages 226formed in the floating stator 220, which correspond to eight secondradial passages 236 formed in the rotor 230, and the first radialpassages 226 and second radial passages 236 may be evenly spaced aboutthe circumference of the shaft seal assembly 200. However, in otherembodiments, different numbers, spacing, and/or configurations of thefirst radial passages 226 and/or second radial passages 236 may be usedwithout departing from the spirit and scope of the shaft seal assembly200 as disclosed and claimed herein.

In an embodiment of the shaft seal assembly 200 not pictured herein, butwhich embodiment is a corollary to that shown in FIGS. 14 & 15. It willbe apparent in light of the present disclosure that in such anembodiment, the rotor 20 will include at least one roller cavityadjacent the shaft 10 with at least one roller positioned therein ratherthan a frictional seal 60. As with the previous embodiments of the shaftseal assembly 200 described herein, the roller(s) may be configured torotatively couple the rotor 20 with the shaft 10. The rotor cavityand/or roller may be also be configured to allow the shaft 10 to moveaxially with respect to the shaft sealing assembly 200.

Multi-Shaft Seal Assembly

FIG. 19 provides a perspective view of a first embodiment a multi-shaftseal assembly 202. It is contemplated that a multi-shaft seal assembly202 may be especially useful in applications wherein two shafts 10 arepositioned in relative close proximity to one another, as shown for theillustrative embodiment pictured herein. The shafts 10 pictured hereinare also oriented such that the longitudinal axes thereof are parallelwith respect to one another. However, the multi-shaft seal assembly 202is not so limited, and other embodiments thereof exist for use withshafts 10 that are oriented differently than those pictured herein.

The illustrative embodiment of the multi-shaft seal assembly 202includes a first seal 240. A sealing portion of the first seal 240surrounds one shaft 10 and may be configured to operate in a mannersubstantially similar to other bearing isolators 18 and/or shaft sealassemblies 25, 200 disclosed herein or otherwise. A sealing portion of asecond seal 250 surrounds the other shaft 10 and also may be configuredto operate in a manner substantially similar to other bearing isolators18 and/or shaft seal assemblies 25, 200 disclosed herein or otherwise.For example, FIG. 21 provides an axial, cross-sectional view of a firstembodiment of the multi-shaft seal assembly 202, wherein both the firstand second seals 240, 250 are configured to operate in a mannersubstantially similar to the bearing isolator 18 shown in FIGS. 13-17.However, in other embodiments of the multi-shaft seal assembly 202,either the first or second seal 240, 250 may be differently configured.For example, the first and second seals 240, 250 may be configured likethe embodiment of a shaft seal assembly 200 shown in FIGS. 18 & 18A.Furthermore, in other embodiments of the multi-shaft seal 202, the firstseal 240 and second seal 250 may be configured differently from oneanother. For example, the first seal 240 may be configured to operate ina manner substantially similar to the bearing isolator 18 shown in FIGS.13-17 and the second seal 250 may be configured to operate in a mannersubstantially similar to the shaft seal assembly 200 shown in FIGS. 18 &18A. Accordingly, the specific internal configuration of either thefirst or second seal 240, 250 in no way limits the scope of themulti-shaft seal assembly 202 as disclosed herein.

As shown in FIG. 21, each seal 240, 250 may be configured to include afixed stator 210, floating stator 220, face plate 212, and a rotor 220,all of which are shown in FIG. 21 as being configured to operate in amanner substantially similar to the embodiment of a bearing isolator 18as shown in FIGS. 13-17, as previously mentioned. The rotor 230 may besecured to a shaft 10 such that the rotor 230 is coupled thereto androtates therewith in any suitable manner (several of which are describedabove for other embodiments of a bearing isolator 18 and/or shaft sealassemblies 25, 200). The fixed stator 210 may be secured to a housing 19in any suitable manner (several of which are described above for otherembodiments of a bearing isolator 18 and/or shaft seal assemblies 25,200 and which include but are not limited to mechanical fasteners 204,chemical adhesives, welding, interference fit, and/or combinationsthereof). One such suitable manner includes fasteners 204 as shown inFIGS. 19, 20, & 22 and corresponding apertures 206. The floating stator220 may be positioned within a portion of an annular recess 216 formedin the fixed stator 10, wherein the exterior axial boundary of theannular recess 216 may be defined by the interior surface of a faceplate 212, which may be engaged with the fixed stator 210 as previouslydescribed for other embodiments of the bearing isolator 18 and shaftseal assemblies 25, 200.

The fixed stator 210, floating stator 220, rotor 230, and/or face plate212 may cooperate to form a labyrinth seal. The fixed stator 210,floating stator 220, and/or the rotor 230 may be constructed in atwo-piece manner. As mentioned, in the illustrative embodiment, thefixed stator 210 may be configured to engage a face plate 212 via aplurality of fasteners 204, which may be distinct from the fasteners 204used to engage the fixed stator 210 with the housing 19. Other methodsand/or structures for engaging the face plate 212 with the fixed stator210 may be used without limitation. Additionally, an interface betweentwo portions of the rotor 230, two portions of the fixed stator 210, thefixed stator 210 and the floating stator 220, the rotor 230 and thefloating stator 220, and/or the rotor 230 and fixed stator 210 may besemi-spherical, as shown for the interface between the rotor 230 andfloating stator 220 for the embodiment pictured in FIG. 21. Furthermore,the seals 240, 250 may be formed with an inlet 214 therein, aspreviously described for the other embodiments of a bearing isolator 18and shaft seal assemblies 25, 200 disclosed herein to provide a sealingfluid to various passages within the multi-shaft seal assembly 202.

To accommodate two shafts 10 in relative close proximity, theillustrative embodiment of a multi-shaft seal assembly 202 employs aconfiguration in which the first and second seals 240, 250 areconfigured in a stacked arrangement (see FIGS. 20 & 21). That is, thefirst seal 240 may reside in a different radially oriented plane thanthat in which the second seal 250 resides. In the illustrativeembodiment, the planes are parallel with respect to one another.However, in other embodiments of the multi-shaft seal assembly 202 notpictured herein, the planes may have other orientations, whichorientations may be dependent at least in part on the orientation of theshafts 10 and/or housing 19.

A collar 241 may be secured to the housing 19 and/or the first seal 240to provide the proper axial spacing for the stacking arrangement of thefirst and second seals 240, 250. In the illustrative embodiment thecollar 241 may be formed separately from either the first seal 240 orthe housing 19, and later secured to the first seal 240 and/or housing19. As clearly shown in FIG. 19B, which provides a rear side perspectiveview of the illustrative embodiment of a multi-shaft seal assembly 202,the collar 241 may be formed with a collar cutaway 242 therein toaccommodate a portion of the second seal 250. As shown, the collarcutaway 242 may be configured with an angled portion to interface withthe exterior surface of the first seal 240.

In most applications, the surface prominently shown in FIG. 19B isadjacent a housing 19 during use of the multi-shaft seal assembly 202.Accordingly, the surface of the collar 241 and/or first seal 240adjacent the housing 19 may be formed with an o-ring channel therein toaccommodate an o-ring. An o-ring so positioned may serve to prevent airand/or other fluid from egress/ingress between the collar 241 andhousing 19 and/or between the first seal 240 and housing 19. Thespecific shape, dimensions, and/or configuration of the collar cutaway242 will vary from one embodiment of the twin-shaft seal assembly 202 tothe next, and may be at least dependent upon the spacing of the shafts10 and/or configuration of the first and second seals 240, 250, and istherefore in no way limiting to the scope of the multi-shaft sealassembly 202. As shown for the illustrative embodiment, the collar 241may be secured to the housing 19 via one or more fasteners 204 andcorresponding apertures 206. However, in other embodiments of themulti-shaft seal assembly 202 pictured herein, the collar 241 may beintegrally formed with a portion of the first seal 240. In still otherembodiments of the multi-shaft seal assembly 202 not pictured herein thecollar 241 may be integrally formed with the housing 19. In anotherembodiment of a multi-shaft seal assembly 202 not pictured herein thecollar 241 may be integrally formed with the second seal 250.Accordingly, the multi-shaft seal assembly 202 is not limited by thespecific configuration of the first collar 241 with respect to thehousing 19, first seal 240, and/or second seal 250.

The collar 241 may serve as an axial spacer between the equipmenthousing and the second seal 250 as clearly shown in FIGS. 20 & 21. Inthis embodiment, the axial dimension of the collar 241 is approximatelyequal to that of the first and second seals 240, 250. However, thecollar 240 may be formed with a collar lip 241 a into which a portion ofthe second seal 250 may seat, as shown in FIG. 21. Accordingly, inapplications wherein the radial dimension of the first and/or secondseal 240, 250 is too great for mounting thereof in the same radial planedue to the spacing of two adjacent shafts 10, the first and second seals240, 250 may be applied to the shafts 10 in an axially offsetconfiguration.

The multi-shaft seal assembly 202 may also include a cutaway 251 formedin a portion of the second seal 250. A cutaway 251 may be required toaccommodate certain configurations of adjacent shafts 10 wherein theshafts 10 are in relative close proximity to one another. As best shownin FIGS. 20 & 22, the configuration of shafts 10 in the illustrativeembodiment of the multi-shaft seal assembly 202 are in relatively closeproximity to one another such that the second seal 250 must be formedwith a cutaway 251 to accommodate adequate clearance with the shaft 10corresponding to the first seal 240. However, in other configurations ofadjacent shafts 10, the multi-shaft seal assembly 202 may not require acutaway 251. Accordingly, the multi-shaft seal assembly 202 is in no waylimited the presence, absence, and/or configuration of a cutaway 251.Generally, a cutaway 251 may reduce the radial dimension of the fixedstator 210 and/or face plate 212, as shown in FIG. 21. However, in otherconfigurations the cutaway 251 may alternatively or additional reducethe radial dimension of the floating stator 220 and/or rotor 230.

Although the illustrative embodiment of a multi-shaft seal assembly 202is configured to accommodate two shafts 10, other embodiments notpictured herein are configured to accommodate more than two shafts 10.Accordingly, the multi-shaft seal assembly 202 is not limited by thenumber of shafts 10 and/or seals 240, 250 associated therewith.

Additional Embodiments of a Shaft Seal Assembly

Another embodiment of a shaft seal assembly 200 is shown in perspectiveview in FIG. 22A. The illustrative embodiment shown in FIG. 22A includesboth a stator 310 and a rotor 320, which may rotate with respect to oneanother. The stator 310 may engage a housing 19 and surround a shaft 10that is rotatable with respect to and extends from the housing 19. Inthe illustrative embodiment, an o-ring 303 positioned in an o-ringchannel 302 formed in the stator 310 may be used to properly engage thestator 310 with the housing 19. However, any other suitable methodand/or structure for adequately engaging the stator 310 with the housing19 may be used with the shaft seal assembly 300 without departing fromthe spirit and scope as disclosed herein.

The rotor 320 may also surround the shaft 10, and it may also be engagedwith the shaft 10 so as to rotate therewith. In the illustrativeembodiment, an o-ring 303 positioned in an o-ring channel 302 formed inthe rotor 320 may be used to properly engage the rotor 320 with theshaft 10. However, any other suitable method and/or structure foradequately engaging the rotor 320 with the shaft 10 may be used with theshaft seal assembly 300 without departing from the spirit and scope asdisclosed herein. It is contemplated that this embodiment may beespecially suited for applications in which the shaft 10 and/or housing19 is oriented in a generally vertical arrangement and extends upwardwith respect to the housing 19, but the application of the shaft sealassembly 300 in no way limits the scope thereof. Furthermore, anyembodiments of a shaft seal assembly 25, 200, 202 may be configured withadvantageous features disclosed herein related to the embodiment of ashaft seal assembly 300 shown in FIGS. 22A-22D without limitation aloneor in combination.

The stator 310 may be formed with a stator body 311 having one or moreaxial projections 314 and/or radial projections 315 extending therefrom.Additionally, an axial projection 314 may extend from a radialprojection 315 or vice versa. The embodiment of a shaft seal assembly300 from FIG. 22A is shown in FIG. 22C with the stator 310 and rotor 320separated from one another. As shown, a shoulder 312 may be formed inthe stator body 311 to provide an interface with a housing 19. An o-ringchannel 302 may be formed in the shoulder 312 to accommodate an o-ring303 to facilitate proper engagement of the stator 310 and housing 19, aspreviously described above. Another o-ring channel 302 may be formed onthe interior surface of the stator body 311 adjacent the shaft 10. Aslip ring 305 may be positioned in this o-ring channel 302 to mitigateegress of lubricant from the housing 19 and ingress of contaminants tothe housing 19 via the space between the shaft 10 and stator 310. Thestator body 311 may also be formed with one or more radial bores 313 tofacilitate an optional sealing fluid (e.g., air, water, etc.) to furthermitigate the egress and/or ingress described above.

The rotor 320 may be formed with a rotor body 321 having one or morerotor axial projections 324 and/or rotor radial projections 325extending therefrom. Additionally, a rotor axial projection 324 mayextend from a rotor radial projection 325 or vice versa. A unitizingring 304 may reside partially within a unitizing ring channel 318 formedin the stator 310 and partially within a rotor unitizing ring channel328 and function to allow only a predetermined amount of relative axialmotion between the stator 310 and rotor 320. From a comparison of FIGS.22B and 22C, it will be apparent to those of ordinary skill in the artthat the various axial projections 314, radial projections 315, axialchannels 316, and/or radial channels 317 formed in the stator 310 maycooperate with various rotor axial projections 324, rotor radialprojections 325, rotor axial channels 326, and/or rotor radial channels327 to create a labyrinth seal having a laborious and/or circuitous pathof one or more axial channels 316 and/or one or more radial channels 317for egress of lubricants from the housing 19 and/or ingress ofcontaminants to the housing 19. An infinite number of configurations forthe various axial projections 314, radial projections 315, axialchannels 316, and/or radial channels 317 formed in the stator 310 maycooperate with various rotor axial projections 324, rotor radialprojections 325, rotor axial channels 326, and/or rotor radial channels327 exist, and accordingly, the specific number, existence, and/orconfiguration thereof in no way limits the scope of the shaft sealassembly 300 as disclosed and claimed herein.

In the illustrative embodiment of a shaft seal assembly 300 shownherein, the axial projections 314, radial projections 315, axialchannels 316, and/or radial channels 317 formed in the stator 310 maycooperate with various rotor axial projections 324, rotor radialprojections 325, rotor axial channels 326, and/or rotor radial channels327 may be configured to form a first cooperating cavity 306 a, a secondcooperating cavity 306 b, and an axial passage 307 for the firstpotential ingress point for contaminants. Referring to FIG. 22D, whichshows the illustrative embodiment of the shaft seal assembly 300 engagedwith a generally vertically oriented shaft 10 protruding upward from ahousing 19, the path contaminants must traverse to pass through theillustrative embodiment of the shaft seal assembly 300 is exceedinglytortuous. The only ingress point is a downwardly oriented terminus of anaxial passage 307, entry to which requires overcoming gravity. After aradial passage 308, contaminants are faced with another axial passage307 requiring overcoming gravity once again. This axial passage 307leads to a first cooperating cavity 306 a. Contaminants retained in thefirst cooperating cavity 306 a may simply drain downward therefrom viagravity. An axial passage 307 at the top of the first cooperating cavity306 a requires contaminants to completely fill the first cooperatingcavity 306 a and then overcome gravity to exit the first cooperatingcavity 306 a via the top axial passage 307.

A radial passage 308 may fluidly connect the axial passage 307 at thetop of the first cooperating cavity 306 a to a second cooperating cavity306 b. In the illustrative embodiment, three sides of the secondcooperating cavity 306 b may be formed via the rotor 320, whichgenerally rotates with the shaft 10 during use. Accordingly,contaminants reaching the second cooperating chamber 306 b may be flungradially outward due to centrifugal force imparted to the contaminantsvia rotation of the rotor 320. If contaminants within the secondcooperating chamber 306 b drain via gravity through an axial passage 307at the bottom of the second cooperating chamber 306 b, thosecontaminants must traverse a radial passage 308 prior to encountering acomparatively long radial passage 308 that leads to another axialpassage 307 adjacent the distal end of an axial projection 314 formed inthe stator 310. Another comparatively long radial passage 308 may be influid communication with the axial passage 307 adjacent the distal endof an axial projection 314 formed in the stator 310, the path throughwhich radial passage 308 may be interrupted by a unitizing ring 304occupying a portion of a unitizing ring channel 318 formed in the stator310 and a portion of a rotor unitizing ring channel 328. Shouldcontaminants traverse this radial passage 308, those contaminants mustalso traverse an axial passage 307 in fluid communication with thatradial passage 308 before contacting the shaft 10. To enter the housing19, contaminants positioned on the shaft 19 between the stator 310 androtor 320 must traverse a slip ring 305 that, in the illustrativeembodiment of a shaft seal assembly 300, may be positioned in an o-ringchannel 302 in the stator 310 adjacent the shaft 10.

In the illustrative embodiment of the shaft seal assembly 300 picturedherein, the various transitions between axial passages 307 and radialpassages 308 may be configured as right angles. Additionally, all axialpassages 307 may be parallel with one another and perpendicular to allradial passages 308. However, in other embodiments the axial passages307 and/or radial passages 308 may have different orientations withoutlimitation. For example, in an embodiment not pictured herein, an axialpassage 307 may be angled at 45 degrees with respect to the rotationalaxis of the shaft 10.

Porous Media Shaft Seal Assembly

Element Listing (FIGS. 23-27)

Description Element No. Shaft 10 Housing 12 Housing contents 13 Porousmedia 14 Sealed surface  14a Open surface  14b O-ring 16 Stator 20Stator groove  20a Pin cavity  20b Stator main body 21 Port  21a Passage 21b Floating stator first portion  22a Floating stator second portion 22b Stator cap 23 Cap groove  23a Connector 24 Pin 26 Seal 30 Sealconvex surface 32 Seal passage 34 Rotor 40 Rotor collar 42 Interfacemember 44 Rotor connector 46 Biasing member 50 Cone sealing structure 60First end 62 Second end 64 Fastener 66 Porous media shaft seal assembly100 

A perspective view of a first illustrative embodiment of a porous mediashaft seal assembly 100 is shown in FIG. 23. Unless otherwise indicated,the orientation of all FIGS. 23 and 25-27 places the fluid side of theporous media shaft seal assembly 100 toward the left of the drawing andthe outboard side toward the right of the drawing. Generally, theembodiment of a porous media shaft seal assembly 100 shown in FIG. 23functions in a manner analogous to that of the shaft seal assembly 25shown in FIG. 1-7 or 9-12.

Generally, the porous media shaft seal assembly 100 may accommodateangular misalignment of the shaft 10, as well as axial and radialmovement thereof using generally the same principles as those previouslyexplained for the shaft seal assembly 25 shown in FIG. 1-7 or 9-12.Accordingly, the stator 20 may include a stator main body 21 and afloating stator first and second portion 22 a, 22 b positioned within acavity formed by the stator main body 21 and a stator cap 23. The seal30 may be engaged with the floating stator first and/or second portion22 a, 22 b about a spherical or semi-spherical interface as previouslydescribed above for the shaft seal assembly 25.

As with the embodiment of a shaft seal assembly 25 shown in FIG. 1-7 or9-12, a seal fluid (which oftentimes may be pressurized, and which maybe a gas, liquid, vapor, and/or combination thereof) may be introducedinto the porous media shaft seal assembly 100 via a port 21 a, which maybe formed in the stator 20. The seal fluid may be communicated to theseal 30 through the stator 20 (e.g., via passages 21 b formed in thefloating stator first and/or second portions 22 a, 22 b). It iscontemplated that in one embodiment, a plurality of radially orientedpassages 21 b may be formed in the floating stator second portion 22 band may serve to communicate seal fluid from an area between the statormain body 21 to the seal 30. These same passages 21 b may correspond toone or more seal passages 34 formed in the seal 30, which seal passages34 also may be radially oriented. In the porous media shaft sealassembly 100, a layer of porous media 14 may be engaged with the surfaceof the seal 30 that faces the shaft 10, as shown in FIG. 23. The porousmedia 14 may comprise one or more sealed surfaces 14 a and one or moreopen surfaces 14 b.

The sealed surfaces 14 a may be configured to be impermeable to adesired fluid and/or group of fluids (which may comprise the sealfluid). Accordingly, the open surface(s) 14 b may be configured to bepermeable to a desired fluid and/or group of fluids (which may comprisethe seal fluid). In this manner, seal fluid may be introduced to theporous media 14 and exit the porous media 14 only at the open surface(s)14 b, which may constitute the active surface of the porous media shaftseal assembly 100. Special compounds are used in the porous air bearingindustry to provide this sealing capability. For the embodiment shown inFIG. 23, it is contemplated that the axial faces of the porous media 14may comprise sealed surfaces 14 a, as well as the surface of the porousmedia 14 positioned adjacent the seal 30. This configuration may serveto retain internal seal fluid pressure, but other configurations ofsealed surfaces 14 a and open surfaces 14 b may be used with the porousmedia shaft seal assembly 100 without limitation. It is furthercontemplated that the interior periphery (or a portion thereof) of theporous media 14 may be configured as an open surface 14 b such that sealfluid may exit the porous media shaft seal assembly 100 along the shaft10.

A perspective view of a second illustrative embodiment of a porous mediashaft seal assembly 100 is shown in FIG. 24. Generally, this embodimentof a porous media shaft seal assembly 100 functions in a manneranalogous to that of the bearing isolator 18 and/or shaft seal assembly200, various embodiments of which are shown in FIGS. 13-18A anddescribed in detail above. However, in the porous media shaft sealassembly 100, a layer of porous media 14 may be engaged with the surfaceof the rotor 40 adjacent the interface between a floating stator firstportion 22 a and the rotor 40 (which may be configured as asemi-spherical interface). Alternatively, a layer of porous media 14 maybe engaged with the surface of the floating stator first portion 22 aadjacent the interface between the floating stator first portion 22 aand the rotor 40. As with the embodiment shown in FIG. 23, the porousmedia 14 in this embodiment may comprise one or more sealed surfaces 14a and one or more open surfaces 14 b.

As with the embodiment of a porous media shaft seal assembly 100 shownin FIG. 23, a seal fluid may be introduced into the porous media shaftseal assembly 100 via a port 21 a, which may be formed in the stator 20.The seal fluid may be communicated to the interface between the floatingstator first portion 22 a and the rotor 40 (e.g., via passages 21 bformed in the floating stator first portion 22 a). For the embodimentshown in FIG. 24, it is contemplated that for most applications it willbe advantageous to configure the porous media 14 on an interior portionof the floating stator first portion 22 a, such that the porous media 14does not rotate and is secured with the stator 20. In one embodiment, aplurality of radially oriented passages 21 b may be formed in thefloating stator first portion 22 a and may serve to communicate sealfluid from a stator groove 20 a to the interface between the floatingstator first portion 22 a and the rotor 40. These same passages 21 b maycorrespond to one or more open surfaces 14 b in the porous media on asurface of the porous media 14 adjacent the floating stator firstportion 22 a. It is further contemplated that the axial faces of theporous media 14 may comprise sealed surfaces 14 a, as well as at least aportion of the surface of the porous media 14 positioned adjacent thefloating stator first portion 22 a (e.g., any portion of that surfacethat does not align with a passage 21 b). This configuration may serveto retain internal seal fluid pressure.

It is further contemplated that the interior periphery (or a portionthereof) of the porous media 14 may be configured as an open surface 14b such that seal fluid may exit the porous media shaft seal assembly 100along the interface between the floating stator first portion 22 a andthe rotor 40. However, other configurations of sealed surfaces 14 a andopen surfaces 14 b may be used with the porous media shaft seal assembly100 without limitation. Furthermore, in any embodiments of the porousmedia shaft seal assembly 100, one or more O-rings (with or without acorresponding groove) may be used to provide a seal between varioussurfaces.

In another embodiment of a porous media shaft seal assembly 100 notpictured herein but similar to that shown in FIG. 24, the rotor 40 maybe comprised to two separate portions biased away from one another (andconsequently, toward the stator 20). The biasing member may be amagnetic field, a spring, or any other suitable method and/or apparatusfor biasing the relevant portions away from one another. The seal fluidmay serve to urge the two portions toward one another. Accordingly, thebiasing member may cooperate with the rotor 40 and stator 20 (and/orfloating stator first and/or second portions 22 a, 22 b) to physicallyseal the housing 12 from the external environment in the instance ofloss of pressurized fluid to the porous media shaft seal assembly 100.

The top portion of another embodiment of a porous media shaft sealassembly 100 is shown in cross-section in FIG. 25. In this embodiment,the rotor 40 may include a rotor collar 42 and an interface member 44.The rotor collar 42 may be engaged with the shaft 10 such that the axialposition of the rotor collar 42 on the shaft 10 may be fixed. Thisengagement may be accomplished via a rotor connector 46, which may be aset screw as shown in the illustrative embodiment. However, any suitablestructure and/or method may be used to adequately engage the rotorcollar 42 with the shaft 10, and the scope of the porous media shaftseal assembly 100 is in no way limited by the structure and/or methodused therefor. The interface member 44 may be configured to be moveablealong a portion of the shaft 10 in the axial dimension. An O-ring 16 maybe positioned in a groove in the interface member 44 adjacent the shaft10 and configured to allow movement of the interface member 44 withrespect to the shaft 10 in the axial dimension with a predeterminedamount of force applied to the interface member 44 in an axial dimensionwith respect to the shaft 10.

A stator 20 may be engaged with a housing 12. This engagement may beaccomplished via any suitable structure and/or method for the specificapplication of the porous media shaft seal assembly 100, including butnot limited to mechanical fasteners, press-fit engagement, chemicaladhesives, and/or combinations thereof. A biasing member 50 may beemployed to urge the interface member 44 of the rotor 40 toward aportion of the stator 20. Accordingly, the axial position of theinterface member 44 on the shaft 10 may be variable in a manner aspreviously described. As with the previously described embodiments, alayer of porous media 14 may be positioned between the stationary androtating portions of the porous media shaft seal assembly 100. Theporous media 14 may comprise one or more sealed surfaces 14 a and one ormore open surfaces 14 b.

A seal fluid may be introduced into the porous media shaft seal assembly100 via a port 21 a, which may be formed in the stator 20. The sealfluid may be communicated to the porous media 14 via one or morepassages 21 b formed in the stator 20. In the embodiment pictured inFIG. 25, it is contemplated that the interface member 44 may rotate withrespect to the stator 20, such that a layer of porous media 14 may bepositioned on the stator 20. In the embodiment shown in FIG. 25, thebiasing member 50 may comprise a single spring that fits over theoutside diameter of the shaft 10. However, other types of biasingmembers 50 may be used without limitation. Shoulders and/orcorresponding recesses formed in the rotor collar 42 and/or interfacemember 44 may be used to adequately retain the biasing member 50 withinthe porous media shaft seal 100.

The seal fluid may be communicated to the porous media 14 in an arrayaround the stator 20. The porous media 14 may be configured such thatonly the surface(s) adjacent a passage 21 b in the stator 20 and thesurface of the porous media 14 adjacent the interface member 44 of therotor 40 are open surfaces 14 b and the remaining surfaces of the porousmedia may be configured as sealed surfaces 14 a. In this configuration,seal fluid may exit the stator 20 adjacent the interface member 44 ofthe rotor 40 (in the direction shown by the arrows in FIG. 25) to forman air barrier therebetween (which may be configured as any airbearing). Accordingly, the flow characteristics of the seal fluid may bemanipulated such that under normal operating conditions, the seal fluidacts against the biasing member 50 and urges the interface member 44away from the porous media 14. If the flow characteristics of the sealfluid deviate in a predetermined manner (e.g., pressure drop), the forceof the biasing member 50 may overcome the force of the seal fluid andcause the interface member 44 to contact the porous media 14, therebyclosing the porous media shaft seal assembly 100 and isolating theinterior thereof from the exterior thereof. However, otherconfigurations of sealed and open surfaces 14 a, 14 b may be usedwithout limitation.

An axial, cross-sectional view of another embodiment of a porous mediashaft seal assembly 100 is shown in FIG. 26. This embodiment is similarto that shown in FIG. 25 and may be configured to function in a similarmanner to that shown in FIG. 25. The rotor collar 42 and interfacemember 44 may engage the shaft 10, and the stator 20 may engage ahousing 12 in any of the manners previously described for the embodimentshown in FIG. 25, and the structure and/or method used therefor in noway limits the scope of the porous media shaft seal assembly 100.

The embodiment shown in FIG. 26 may employ multiple biasing members 50between the rotor collar 42 and interface member 44. Accordingly, in theembodiment shown in FIG. 25, one or more biasing members may bepositioned around the periphery of the shaft 10 in an array or otherarrangement. It is contemplated that both the embodiment shown in FIG.25 and that shown in FIG. 26 may be configured to mount directly to ahousing 12 having a rotating shaft 10 protruding from the housing 12, oreither embodiment may be configured to be used in conjunction with astuffing box, wherein the porous media shaft seal assembly 100 may beused in addition to or in lieu of packing material.

A cone sealing structure 60 is shown in the embodiment of a porous mediashaft seal assembly 100 shown in FIG. 27A. In this embodiment, the conesealing structure 60 may be mounted internally or externally to ahousing 12 depending on the specific application, as described infurther detail below. The cone sealing structure 60 may include a firstend 62 and a second end 64. In the illustrative embodiment shown indetail in FIG. 27B, the first end 62 may provide an engagement area forthe shaft 10 and the second end 64 may provide an engagement area withthe rotor 40. The first end 62 may be engaged with a shaft 10 via afastener 66 engaging a portion of the first end 62. The second end 64may be engaged with a rotor 40 via a fastener 66 engaging a portion ofthe second end 64. Both fasteners may be configured as elastomericmembers, wherein the fastener for the first end 62 comprises anelastomeric band and the fastener for the second end 64 comprises anelastomeric ring. Each fastener 66 may be configured to allow a certainamount of movement of the first end 62 with respect to the second end64. However, any suitable fastener 66 may be used without limitation,including but not limited to chemical adhesives, other mechanicalfasteners, and/or combinations thereof. An O-ring 16 may be positionedbetween a bottom surface of the rotor 40 and the shaft 10 and configuredto allow movement of the rotor 40 with respect to the shaft 10 in theaxial dimension with a predetermined amount of force applied to theinterface member 44 in an axial dimension with respect to the shaft 10.

As in previous embodiments described herein, a biasing member 50 may beused to bias a portion of the cone sealing structure 60 toward or awayfrom a second surface, which may be a portion of a housing 12 or astator 20 mounted thereto. In the illustrative embodiment shown in FIG.27A, a stator 20 may be engaged with a housing 12, which engagement maybe accomplished via any suitable structure and/or method as previouslydisclosed herein for other embodiments of the porous media shaft sealassembly 100 without limitation. The force of the biasing member 50 maybe opposed by pressurized fluid flowing through a portion of the porousmedia shaft seal assembly 100. The force of the biasing member 50 may besupplemented by a fluid within a vessel acting on the cone sealingstructure 60 in a substantially parallel direction to that at which thebiasing member 50 acts on the cone sealing structure 60. Additionally oralternatively, the cone sealing structure 60 may have an integratedbiasing member between the first and second ends 62, 64.

Generally, it is contemplated that porous media 14 may be mostadvantageously applied to and/or engaged with a nonrotating portion ofthe porous media shaft seal assembly 100 to limit complexity forproviding seal fluid to the porous media. For the embodiments shown inFIGS. 27A-27C, the cone sealing structure 60 may rotate with the shaft10 via the engagement between the first end 62 and the shaft 10, whichmay consequently cause the second end 64 and rotor 40 to rotate.Accordingly, it is contemplated that porous media 14 may mostadvantageously be applied to and/or engaged with a surface of the stator20 facing the rotor 40 for those embodiments. However, in otherembodiments, it may be advantageous to apply porous media 14 todifferent elements and/or surfaces thereof. For example, in anembodiment not pictured herein, the cone sealing structure 60 may beengaged with a housing 12 adjacent the second end 64, such that the conesealing structure 60 does not rotate with the shaft 10. A rotor 40 maybe engaged with the shaft 10 such that it rotates therewith, and suchthat a portion of the rotor 40 is positioned adjacent the first end ofthe cone sealing structure 60. Porous media 14 may be engaged with thefirst end 62 either directly via the first end 62 of the cone sealingstructure or via a stator 20 engaged with the cone sealing structure 60.

In either configuration (stationary or rotating cone sealing structure60), seal fluid may be communicated to the porous media 14 of the porousmedia shaft seal assembly 100 via one or more ports 21 a and/or passages21 b as previously described for other embodiments of the porous mediashaft seal assembly 100. The porous media 14 may be configured withsealed surfaces 14 a and open surfaces 14 b to retain internal sealfluid pressure, as previously described for other embodiments of theporous media shaft seal assembly 100. Also as previously described forother embodiments, the flow characteristics of the seal fluid may becontrolled such that under normal operating conditions, the seal fluidacts against the biasing member 50 and urges the rotor 40 away from theporous media 14. If the flow characteristics of the seal fluid deviatein a predetermined manner (e.g., pressure drop), the force of thebiasing member 50 may overcome the force of the seal fluid and cause therotor 40 to contact the porous media 14, thereby closing the porousmedia shaft seal assembly 100 and isolating the interior thereof fromthe exterior thereof. However, other configurations of sealed and opensurfaces 14 a, 14 b may be used without limitation.

Another embodiment of a porous media shaft seal assembly 100 using acone sealing structure 60 is shown in detail in FIG. 27C. Thisembodiment may function in a manner substantially the same as theembodiment shown in FIG. 27B. However, the porous media 14 may beconfigured as a ring embedded in the stator 20. The porous media 14 maycomprise sealed surfaces 14 a and open surfaces 14 b, as previouslydescribed for other embodiments of the porous media shaft seal assembly100. The porous media 14 may be secured to the stator 20 via anysuitable method and/or structure, including but not limited tomechanical interference, mechanical fasteners, chemical adhesives,and/or combinations thereof.

It is contemplated that the embodiments shown in FIGS. 27A-27C may bepositioned in a stuffing box of a pump or other housing. The conesealing structure 60 may be used in place of packing, which is typicallyemployed in a stuffing box. Alternatively, the embodiments shown inFIGS. 27A-27C may be mounted outside of a housing 12 rather than withina stuffing box.

In the various embodiments pictured in FIGS. 25-27, the seal fluid flowcharacteristics (pressure, flow rate, configuration of surface on whichseal fluid flow acts) required to overcome the force of the biasingmember 50 and separate the porous media 14 from the opposing faceproduces a pressurized fluid barrier between the porous media 14 and theopposing face. However, unlike mechanical seals found in the prior art,the porous media shaft seal 100 is not sensitive to the clearancebetween the porous media 14 and the opposing face—as long as there is aclearance, the seal fluid pressure may act to prevent product egressfrom the porous media shaft seal assembly 100 and contaminant ingress tothe porous media shaft seal assembly 100. Furthermore, in theembodiments shown in FIGS. 25-27, the fluid pressure of the productwithin the vessel (or housing 12) may urge the porous media 14 andopposing face together to close any gap therebetween.

The porous media 14 may be comprised of carbon graphite, or any othersuitable natural or synthetic material. It is contemplated that theporous media 14 may have characteristics that allow fluid pressure to beevenly distributed throughout the porous media 14. Additionally, it iscontemplated that certain surfaces of the porous media 14 may beconfigured as sealed surfaces 14 a such that fluid within the porousmedia 14 may not exit the porous media 14 via those sealed surfaces 14a. The sealant used to prevent seal fluid exiting the porous media 14may be any suitable sealant for the particular application of the porousmedia shaft seal assembly 100, and in some applications may be comprisedof an epoxy material. The porous media 14 may be engaged with and/orsecured to the desired element using any suitable method and/orstructure including but not limited to mechanical fasteners, press-fitsecurement, O-rings 16, chemical adhesives, and/or combinations thereofwithout limitation.

Typically during operation, the porous media 14 may become saturatedwith the seal fluid introduced through port 21 a (which seal fluid maybe communicated to the porous media 14 via one or more passages 21 b inthe stator 20 and/or seal passages 34 in the seal 30), and consequentlyflow out of the porous media 14 through any open surface 14 a at agenerally predictable and predetermined rate. Accordingly, the porousmedia 14 may provide a throttle to the seal fluid flow regardless of theclearance between the open surfaces 14 a of the porous media 14 andadjacent components (e.g., the shaft 10 in FIG. 23). This results in theconsumption of seal fluid to be dictated by the characteristics of theporous media 14 rather than the clearance between the porous media 14and the other relevant structure. Accordingly, in such a configurationthis clearance may dictate the pressure of the product within thehousing 12 and/or other structure that the porous media shaft sealassembly 100 can effectively seal. If air is used as the seal fluid,then the air may act as a lubricant between the porous media 14 andadjacent component. This configuration may allow for lower airconsumption and a more predictable rate thereof than that compared withproduct seals found in the prior art.

Additional Aspects of a Shaft Seal Assembly

Element Listing (FIGS. 28-301

Description Element No. Shaft seal assembly 10 Housing 12 Shaft 14 Shaftradial gap 15 Drive ring 16 Housing radial gap 17 O-ring 18 Sealing ring19 Stator 20 Stator main body  20a Stator/shaft clearance 21 Statorinward radial projection 22 Annular recess  22a Radial stator/rotorclearance 23 Barrier 24 Exterior groove  24a Shoulder  24b Axialstator/rotor clearance 25 Atypical stator/rotor clearance  25aCollection groove 26 Drain  26a Ramped projection 27 Ramp surface  27aInboard wall  28a Outboard wall  28b Floor  28c Stator sealing ringgroove 29 Rotor 30 Rotor main body  30a Rotor axial projection 32 Rotorramped projection 37 Rotor ramp surface  37a Rotor sealing ring groove39

In an aspect, a shaft seal assembly 10 such as that shown in FIGS. 28-30herein may be designed specifically to provide a level of protection tothe industry standard IP-66 level, as defined by the InternationalElectrotechnical Commission (IEC) IP level of protection codes (IECstandard 60529). In an aspect of a shaft seal assembly 10 shown in FIGS.28A-30, the shaft seal assembly 10 may achieve this level of performancein a much shorter axial length (in an aspect, 0.375 inches; 9.5 mm, butnot limited thereto unless so indicated in the following claims) thanhas been previously possible. Previously, such a level of protectionrequired an axial length of at least 0.700 inches; 1.778 cm; which isnearly twice as much axial length than what is possible with the shaftseal assembly 10 according to the present disclosure. Providing thislevel of protection in a smaller shaft seal assembly 10 allows the IP-66level of protection to be applied to smaller size rotating equipmentthan was possible in the prior art.

In an aspect, the shaft seal assembly 10 shown in FIGS. 28-30 maycomprise a stator 20 and a rotor 30. Generally, the stator 20 and rotor30 may cooperate so as to prevent ingress of contaminants to a housing12 having a shaft 14 protruding therefrom, while simultaneously preventegress of lubricant from the housing 12. The stator 20 of the shaft sealassembly 10 may include a stator main body 20 a and may be mounted to arelatively stationary housing 14 (which may be a housing 14 having anelectrical motor therein, but which housing 14 is not so limited unlessso indicated in the following claims).

The rotor 30 may include a rotor main body 30 a and may be engaged witha rotatable shaft 14 protruding from the housing 12 such that the rotor30 rotates with a shaft 14. In an aspect, the rotor 30 may be engagedwith the shaft 14 via a drive ring 16. The drive ring 16 may beconstructed of an elastomeric material and may be configured to seal ashaft radial gap 15 between the shaft 16 and the rotor 30. The drivering 16 may also be configured to cause the rotor 20 to rotate with theshaft 16.

The stator 20 may be engaged with the housing 12 via an O-ring 18, whichO-ring 18 may be employed in conjunction with an interference fitbetween an external surface of the stator 20 and an interior surface ofthe housing 12. In an aspect, an exterior portion of the stator 20 maybe configured with a stair-step annular channel into which the O-ring 18may be positioned. The stair-step feature of the annular channel may bepositioned on the inboard side of the annular channel such that theoutboard side of the annular channel is deeper (i.e., greater in theradial dimension) than the inboard side of the annular channel. It iscontemplated that such a configuration of an annular channel may easeinstallation of the shaft seal assembly 10 into a housing 12, whilesimultaneously providing adequate sealing between the stator 20 and thehousing 12 at least in part via the O-ring 18. The O-ring 18 may beconstructed of an elastomeric material and may be configured to seal ahousing radial gap 17 between the housing 12 and the stator 20. However,the stator 20 may be engaged with and/or secured to a housing 12 and therotor 30 may be engaged with and/or secured to a shaft 14 using anysuitable structures and/or methods (several of which are described abovefor other embodiments of a bearing isolator 18 and/or shaft sealassemblies 10, 25, 200 and which include but are not limited tomechanical fasteners, chemical adhesives, welding, interference fit,and/or combinations thereof) without limitation unless so indicated inthe following claims.

In an aspect of a shaft seal assembly 10 as shown in FIGS. 28-30, theentire rotor 30 may be positioned within a portion of the stator 20,such that the rotor 30 may be effectively encapsulated by the stator 20.That is, the shaft seal assembly 10 may be configured such that thesurfaces thereof that are directly exposed to the exterior environmentmay be surfaces of the stator 20 rather than one or more surfaces of therotor 30, such that the entire rotor 30 is positioned inboard withrespect to at least one surface of the stator 20. It is contemplatedthat such a configuration may provide for superior sealing attributes ina smaller axial dimension when compared to the prior art.

The shaft seal assembly 10 may be configured to effectively seal (and/ormitigate) contamination from entering the housing 12. In an aspect, anexterior stator inward radial projection 22 may form a stator/shaftclearance 21 between the distal end of the exterior stator inward radialprojection 22 and the shaft 14. The resulting stator/shaft clearance 21may be configured as a close gap seal clearance between the exteriorstator inward radial projection 22 and the shaft 14, which close gapseal clearance may be between 0.018 inches (0.457 mm) and 0.007 inches(0.178 MM). This close gap seal clearance may serve to prevent and/ormitigate ingress of contaminants due to the small space available tosuch contaminants. Any contaminants that do enter the shaft sealassembly 10 through the stator/shaft clearance 21 may subsequentlyencounter a first radial stator/rotor clearance 22. In an aspect, afirst radial stator/rotor clearance 22 may be formed between generallyradially oriented corresponding surfaces of the stator 20 and rotor 30.

The first radial stator/rotor clearance 23 may be in communication withand/or lead to an axial stator/rotor clearance 25. As shown, the firstradial stator/rotor clearance 23 may be perpendicular to the axialstator/rotor clearance 25, but other orientations between them may beused (e.g., less than ninety degrees, greater than ninety degrees)without limiting the scope of the shaft seal assembly 10 unless soindicated in the following claims.

The axial stator/rotor clearance 23 may be in communication with and/orlead to a second radial stator/rotor clearance 25. As shown, the secondradial stator/rotor clearance 23 may be perpendicular to the axialstator/rotor clearance 25, but other orientations between them may beused (e.g., less than ninety degrees, greater than ninety degrees)without limiting the scope of the shaft seal assembly 10 unless soindicated in the following claims. Generally, it is contemplated that inan aspect of the shaft seal assembly 10 the radial stator/rotorclearance(s) 23 and/or axial stator/rotor clearance(s) 25 may beconfigured to impede ingress of contaminants into the shaft sealassembly 10.

Contaminants passing through the radial stator/rotor clearance(s) 23and/or axial stator/rotor clearance(s) 25 may encounter a collectiongroove 26, which may be formed in the stator 20 and which may berelatively large in size compared to the radial stator/rotorclearance(s) 23 and/or axial stator/rotor clearance(s) 25. For example,in an aspect the axial length of the collection groove 25 may be morethan ten times greater than the axial stator/rotor clearance 25 and theradial depth of the collection groove 25 may be more than ten timesgreater than the radial depth of the radial stator/rotor clearance(s)23.

Referring now specifically to FIG. 28C, the limit on the inboardradially oriented surface of the collection groove 26 (wherein “inboard”is generally in the direction toward the left side of FIG. 28C and“outboard” is generally in the direction toward the right side of FIG.28C) may be formed as an inboard wall 28 a. The outboard radiallyoriented surface of the collection groove 26 may be formed as anoutboard wall 28 b. Together, the inboard wall 28 a and the outboardwall 28 b may serve to define the width of the collection groove 26(wherein “width” is used do denote the axial dimension of the collectiongroove 26). In an aspect of the shaft seal assembly 10, the height ofthe inboard wall 28 a (i.e., radial dimension) may great enough toaccommodate a predetermined volume of contaminants within the collectiongroove 26 without rising to a level that would cause the contaminants toflow over the distal end of the inboard wall 28 a.

During operation, it is contemplated that the rotor 30 may impartcentrifugal force to contaminants passing through the radialstator/rotor clearance(s) 23 and/or axial stator/rotor clearance(s) 25and encountering the collection groove 26. This centrifugal force maycause the contaminants to move radially outward to the axially orientedsurface of the collection groove 26, which surface is referred to hereinas a floor 28 c. Referring again to FIGS. 28B and 28C, contaminants incontact with the floor 28 c, inboard wall 28 a, and/or outboard wall 28b may drain via gravity toward the lower portion of the collectiongroove 26, and exit the shaft seal assembly through a drain 26 a influid communication with the collection groove 26. Generally, a drain 26a may be formed in a portion of an exterior groove 24 a (which exteriorgroove 24 is discussed in further detail below) to provide a fluidpassageway from the collection groove 26 to an exterior groove 24 a.

In an aspect, it may be advantageous to have the drain 26 a positionedat the lowest point of the collection groove 26 to aide expulsion ofcontaminants from the shaft seal assembly 10. In an additional aspect,it may be advantageous to position a barrier 24 adjacent the drain 26 aand on the outboard side thereof. Still referring to FIG. 28C, a barrier24 may be configured as an annular, radially extending wall. It iscontemplated that such a barrier 24 may prevent direct ingress ofcontaminants into the shaft seal assembly 10 and/or collection groove26. In an aspect of the shaft seal assembly 10, the distal edges of thebarrier 24 may be radiused and/or smooth. As shown in FIGS. 28B and 28C,the corners on the distal end of the barrier 24 may be curved orotherwise configured such that there is no right angle thereon. It iscontemplated that such a configuration may at least prevent unintendedcatching and/or snagging of foreign objects on the stator 20, which mayincrease safety of operators near the shaft seal assembly 10.

Additionally, an annular barrier 24 like that shown in FIGS. 28 and 29may facilitate an exterior groove 24 a, which may be formed as anannular channel on an axially oriented exterior surface of the stator20. The annular barrier 24 may cooperate with an annular shoulder 24 bto form two radially oriented walls of an exterior groove 24 a. It iscontemplated that an exterior groove 24 a may serve to guidecontaminants on the outboard face of the housing 12 around the openingof the housing 12 (into which a portion of the shaft seal assembly 10may be positioned), thereby reducing the likelihood of the contaminantsentering the shaft seal assembly 10 via the stator/shaft clearance 21and/or reducing the exposure of the stator/shaft clearance 21 tocontaminants on the outboard face of the housing 12.

The rotor 30 may be formed with a rotor axial projection 32. In anaspect of the shaft seal assembly 10 it is contemplated that a rotoraxial projection 32 may cooperate with an annular recess 22 a formed inthe stator inward radial projection 22 to form one or more radialstator/rotor clearances 23 and/or one or more axial stator/rotorclearances 25. Although an aspect of the shaft seal assembly 10 shown inFIGS. 28 and 29 depicts two radial stator/rotor clearances 23 with oneaxial stator/rotor clearance 25 positioned therebetween adjacent therotor axial projection 32, the scope of the present disclosure is not solimited unless indicated in the following claims. Accordingly, in otheraspects of the shaft seal assembly 10 additional rotor axial projections32 may be formed in the rotor 30 along with cooperating additionalannular recesses 22 a formed in the stator inward radial projection tofacilitate additional radial stator/rotor clearances 23 and/or one ormore axial stator/rotor clearances 25. For example, and as described infurther detail below, a sealing ring 19 between the stator 20 and therotor 30 may be arranged such that an axial rotor/stator clearance 25may be positioned on either side of the sealing ring 19.

A phenomena observed in the study of the prior art is that air movementcaused by the rotation of the rotor 30 inside a large annular channel(such as the collection groove 26) may cause the formation of alubricant bubble. The lubricant bubble may form when air movement causedby the rotation the rotor 30 impedes contaminants within the collectiongroove 26 from exiting the shaft seal assembly 10 via the drain 26 a. Ifthe lubricant bubble grows large enough such that it contacts the rotor30, a seal is likely to fail due to leakage of contaminants through theseal and into the housing 12. Configuring the collection groove 26 suchthat the radial dimension (depth) thereof is sufficiently large inrelation to the diameter of the shaft 14 to prevent and/or mitigate thelikelihood of a lubricant bubble contacting the rotor 30 increases theperformance capabilities of the shaft seal assembly 10.

In an aspect of the shaft seal assembly 10 shown in FIGS. 28 and 29, thedimensions of the collection groove 26 may be correlated with theoverall length (axial dimension) of the shaft seal assembly 10. Forexample, if the overall length of the shaft seal assembly 10 is 0.375inches, the collection groove 26 may be configured such that it is 0.150inches deep and 0.175 inches wide. In such and aspect the width of thecollection groove 26 may be approximately 46.7% of the overall length ofthe shaft seal assembly 10 and the depth of the collection groove 26 maybe approximately 40.0% of the overall length of the shaft seal assembly10. However, the shaft seal assembly 10 may employ other relativedimensions of the overall length of the shaft seal assembly 10 withrespect to the depth and/or width of the collection groove 26 withoutlimitation unless so indicated in the following claims.

In an aspect, if the diameter of the shaft 14 is 2.0 inches, the depthof the collection groove 26 may be 0.375 inches. Accordingly, the depthof the collection groove 26 may be approximately 19% of the diameter ofthe shaft 14. The radial dimension (width) of the collection groove 26may be 0.375 inches, such that also may be approximately 19% of thediameter of the shaft 14. However, in other aspects of the shaft sealassembly 10 the depth and/or width of the collection groove 26 may begreater than approximately 19% of the diameter of the shaft 14 withoutlimitation unless so indicated in the following claims. And in stillfurther aspects of the shaft seal assembly 10 the depth and/or width ofthe collection groove 26 may be less than approximately 19% of thediameter of the shaft 14 without limitation unless so indicated in thefollowing claims.

A sealing ring 19 may be positioned between the stator 20 and rotor 30in an inboard direction with respect to the collection groove 26. Thesealing ring 19 may serve as an additional barrier for ingress ofcontaminants into the housing 12 through the seal and/or from egress oflubricant from the housing 12. A stator sealing ring groove 29 and arotor sealing ring groove 39 may cooperate to properly position thesealing ring 19 between the stator 20 and rotor 30. In an aspect of theshaft seal assembly 10 shown in FIGS. 28 and 29, the shaft seal assembly10 may be configured such that an axial stator/rotor clearance 25 leadsto the sealing ring 19 from the outboard side thereof, and such thatanother axial stator/rotor clearance 25 leads to the sealing ring fromthe inboard side thereof.

In an aspect of the shaft seal assembly 10 shown in FIG. 28, the width(axial dimension) of both the stator sealing ring groove 29 and therotor sealing ring groove 39 may be approximately equal to one anotherand to the cross-sectional width of the sealing ring 19. However, asdescribed below other configurations exist, and the specificconfiguration of the stator sealing ring groove 29 and rotor sealingring groove 39 in no way limit the scope of the shaft seal assembly 10unless so indicated in the following claims.

In an aspect, the sealing ring 19 may be static with respect to therotor 30, and the sealing ring 19 may be configured such that it doesnot rotate with the shaft 14. One benefit of a static sealing ring 19that does not rotate with the rotor 30 and/or shaft 14 is that thesealing ring 19 may provide for and function as another close-clearancegap seal in a manner similar to that previously described for thestator/shaft clearance 21. The sealing ring 19 simultaneously may beconfigured such that it is compliant in that it may allow for the rotor20 to move both radially and axially with corresponding movements of theshaft 12 while preventing and/or mitigating metal-to-metal contacttypically associated with those types of shaft 12 movements. In anaspect, preventing and/or mitigating metal-to-metal contact generallyincreases the longevity of the shaft seal assembly 10 and/or preventsand/or mitigates premature failure thereof.

In an aspect, the shaft seal assembly 10 shown in FIGS. 28 and 29 may bedisassembled, unlike many prior art seals and/or bearing isolators.Additionally, an aspect of this shaft seal assembly 10 having a portionof the stator 20 be the most outboard portion of the entire shaft sealassembly 10 (i.e., 12) may reduce the likelihood of separation of therotor 30 from the stator 20 during installation of the shaft sealassembly 10 with an equipment housing 12. That is, a portion of thestator inward radial projection 22 immediately adjacent the rotor 30(i.e., in an aspect, the distal portion of the stator inward radialprojection 22) may prevent and/or mitigate unwanted movement of therotor 30 in an axially outboard direction during installation of theshaft seal assembly 10 as the rotor 30 engages the shaft 14. Because therotor 30 may be secured to the shaft 14 via a drive ring 16 havingelastomeric properties, it is contemplated that in such a configurationa predetermined amount of axially directed force will be required topush the rotor 30 onto the proper position of the shaft 14. It iscontemplated that to install the shaft seal assembly 10, a user mayapply axially directed force to the outboard surface of the statorinward radial projection 22 (which surface may be collinear with theoutboard surface of the barrier 24), and temporary engagement betweenthe inboard surface of the stator inward radial projection 22 and therotor 30 during installation may communicate that force to the rotor 30so as to move it axially in the same direction as the stator 20 untilthe shaft seal assembly 10 is properly located with respect to thehousing 12 and the shaft 14. The stator 20 may be formed with an annularshoulder 24 b (as previously discussed in relation to an exterior groove24 a that may be formed in the stator 20), which may serve at least inpart to properly locate the stator 20 and/or shaft seal assembly 10 withrespect to the housing 12.

In an aspect of the shaft seal assembly 10 shown in FIG. 29, the statorsealing ring groove 29 and/or rotor sealing ring groove 39 may beconfigured differently than those shown in the shaft seal assembly inFIG. 28. The cross-sectional area of the rotor sealing ring groove 39may be less in an aspect of the shaft seal assembly 10 shown in FIG. 29than in that shown in FIG. 28. The smaller cross-sectional area may be aresult of reduced width (in the axial dimension) and/or depth (in theradial dimension). In this aspect, a smaller volume of a sealing ring 19is positioned within the rotor sealing ring groove 39 when compared tothe volume of a sealing ring 19 positioned within the rotor sealing ringgroove 39 shown in FIG. 28. It is contemplated that the rotor sealingring groove 39 advantageously may be deep enough to prevent the sealingring 19 from becoming axially misaligned with the rotor sealing ringgroove 39 during installation. It is further contemplated thatconfiguring the rotor sealing ring groove 39 with a width approximatelyequal to the cross-sectional width of the sealing ring 19 may serve tomitigate and/or prevent axially misalignment between the sealing ring 19and the rotor sealing ring groove 39 during installation of the shaftseal assembly 10.

Furthermore, the cross-sectional area of the stator sealing ring groove29 may be less in an aspect of the shaft seal assembly 10 shown in FIG.29 than in that shown in FIG. 28. The smaller cross-sectional area maybe a result of reduced width (in the axial dimension) and/or depth (inthe radial dimension). In other aspects of a shaft seal assembly 10 thestator sealing ring groove 29 and/or rotor sealing ring groove 39 may bedifferently configured without limitation unless so indicated in thefollowing claims. Accordingly, the specific amount of O-ring 17 that ispositioned within the annular groove in the rotor and the specificamount of O-ring 17 that is positioned within the annular groove in thestator in no way limits the scope of the present disclosure unless soindicated in the following claims. It is contemplated that for someapplications of the shaft seal assembly 10, it may be advantageous toincrease the depth of the stator sealing ring groove 29 to accommodateradial expansion of the sealing ring 19. However, it may be desirable toensure that the depth of the stator sealing ring groove 29 is selectedsuch that it is not greater than the cross-sectional width of thesealing ring 19 such that when the sealing ring 19 is at the radiallimit of the stator sealing ring groove 29 contaminants do not have astraight path between the sealing ring 19 and the rotor 30 to theinboard side of the shaft seal assembly 10.

Further aspects of a shaft seal assembly 10 are shown in FIGS. 30 & 30A,which provides an axial, cross-sectional view of another shaft sealassembly 10. Generally, this shaft seal assembly 10 shown in FIG. 30 mayprovide some or all of the benefits and/or features previously describedfor the shaft seal assemblies 10 disclosed herein, and specificallythose shown in FIGS. 28 and 29, without limitation unless so indicatedin the following claims.

Accordingly, in an aspect, the shaft seal assembly 10 shown in FIGS. 30& 30A may comprise a stator 20 and a rotor 30. Generally, the stator 20and rotor 30 may cooperate so as to prevent ingress of contaminants to ahousing 12 having a shaft 14 protruding therefrom, while simultaneouslyprevent egress of lubricant from the housing 12. The stator 20 of theshaft seal assembly 10 may include a stator main body 20 a and may bemounted to a relatively stationary housing 14 (which may be a housing 14having an electrical motor therein, but which housing 14 is not solimited unless so indicated in the following claims).

The rotor 30 may include a rotor main body 30 a and may be engaged witha rotatable shaft 14 protruding from the housing 12 such that the rotor30 rotates with a shaft 14. In an aspect, the rotor 30 may be engagedwith the shaft 14 via a drive ring 16. The drive ring 16 may beconstructed of an elastomeric material and may be configured to seal ashaft radial gap 15 between the shaft 16 and the rotor 30. The drivering 16 may also be configured to cause the rotor 20 to rotate with theshaft 16.

The stator 20 may be engaged with the housing 12 via an O-ring 18, whichO-ring 18 may be employed in conjunction with an interference fitbetween an external surface of the stator 20 and an interior surface ofthe housing 12. In an aspect, an exterior portion of the stator 20 maybe configured with a stair-step annular channel into which the O-ring 18may be positioned. The stair-step feature of the annular channel may bepositioned on the inboard side of the annular channel such that theoutboard side of the annular channel is deeper (i.e., greater in theradial dimension) than the inboard side of the annular channel. It iscontemplated that such a configuration of an annular channel may easeinstallation of the shaft seal assembly 10 into a housing 12, whilesimultaneously providing adequate sealing between the stator 20 and thehousing 12 at least in part via the O-ring 18. The O-ring 18 may beconstructed of an elastomeric material and may be configured to seal ahousing radial gap 17 between the housing 12 and the stator 20. However,the stator 20 may be engaged with and/or secured to a housing 12 and therotor 30 may be engaged with and/or secured to a shaft 14 using anysuitable structures and/or methods (several of which are described abovefor other embodiments of a bearing isolator 18 and/or shaft sealassemblies 25, 200 and which include but are not limited to mechanicalfasteners, chemical adhesives, welding, interference fit, and/orcombinations thereof) without limitation unless so indicated in thefollowing claims.

In an aspect of a shaft seal assembly 10 as shown in FIGS. 30 & 30A, theentire rotor 30 may be positioned within a portion of the stator 20,such that the rotor 30 may be effectively encapsulated by the stator 20.That is, the shaft seal assembly 10 may be configured such that thesurfaces thereof that are directly exposed to the exterior environmentmay be surfaces of the stator 20 rather than one or more surfaces of therotor 30, such that the entire rotor 30 is positioned inboard withrespect to at least one surface of the stator 20. It is contemplatedthat such a configuration may provide for superior sealing attributes ina smaller axial dimension when compared to the prior art.

The shaft seal assembly 10 may be configured to effectively seal (and/ormitigate) contamination from entering the housing 12. In an aspect, anexterior stator inward radial projection 22 may form a stator/shaftclearance 21 between the distal end of the exterior stator inward radialprojection 22 and the shaft 14. The resulting stator/shaft clearance 21may be configured as a close gap seal clearance between the exteriorstator inward radial projection 22 and the shaft 14. This close gap sealclearance (having dimensions as previously disclosed herein) may serveto prevent and/or mitigate ingress of contaminants due to the smallspace available to such contaminants. Any contaminants that do enter theshaft seal assembly 10 through the stator/shaft clearance 21 maysubsequently encounter a first radial stator/rotor clearance 22. In anaspect, a first radial stator/rotor clearance 22 may be formed betweengenerally radially oriented corresponding surfaces of the stator 20 androtor 30.

The first radial stator/rotor clearance 23 may be in communication withand/or lead to an axial stator/rotor clearance 25. As shown, the firstradial stator/rotor clearance 23 may be perpendicular to the axialstator/rotor clearance 25, but other orientations between them may beused (e.g., less than ninety degrees, greater than ninety degrees)without limiting the scope of the shaft seal assembly 10 unless soindicated in the following claims.

The axial stator/rotor clearance 23 may be in communication with and/orlead to a second radial stator/rotor clearance 25. As shown, the secondradial stator/rotor clearance 23 may be perpendicular to the axialstator/rotor clearance 25, but other orientations between them may beused (e.g., less than ninety degrees, greater than ninety degrees)without limiting the scope of the shaft seal assembly 10 unless soindicated in the following claims. Generally, it is contemplated that inan aspect of the shaft seal assembly 10 the radial stator/rotorclearance(s) 23 and/or axial stator/rotor clearance(s) 25 may beconfigured to impede ingress of contaminants into the shaft sealassembly 10.

Contaminants passing through the radial stator/rotor clearance(s) 23and/or axial stator/rotor clearance(s) 25 may encounter a collectiongroove 26, which may be formed in the stator 20 and which may berelatively large in size compared to the radial stator/rotorclearance(s) 23 and/or axial stator/rotor clearance(s) 25. For example,in an aspect the axial length of the collection groove 25 may be morethan ten times greater than the axial stator/rotor clearance 25 and theradial depth of the collection groove 25 may be more than ten timesgreater than the radial depth of the stator/rotor clearance(s) 23. Thecollection groove 26 may be configured in any manner as previouslydescribed for the shaft seal assemblies 10 shown in FIGS. 28 and 29without limitation unless so indicated in the following claims.

A limit on the inboard radially oriented surface of the collectiongroove 26 (wherein “inboard” is generally in the direction toward theleft side of FIG. 30 and “outboard” is generally in the direction towardthe right side of FIG. 30) may be formed as an inboard wall 28 a. Theoutboard radially oriented surface of the collection groove 26 may beformed as an outboard wall 28 b. Together, the inboard wall 28 a and theoutboard wall 28 b may serve to define the width of the collectiongroove 26 (wherein “width” is used do denote the axial dimension of thecollection groove 26). In an aspect of the shaft seal assembly 10, theheight of the inboard wall 28 a (i.e., radial dimension) may be greatenough to accommodate a predetermined volume of contaminants within thecollection groove 26 without rising to a level that would cause thecontaminants to flow over the distal end of the inboard wall 28 a.

The stator 20 may be formed with a ramped projection 27 extendingradially inward from the stator main body 20 a. The ramped projection 27may be formed with a ramp surface 27 a at the distal end thereof. Therotor 30 may be formed with a rotor ramped projection 37 extendingradially outward from the rotor main body 30 a, which may be formed witha rotor ramp surface 37 a at the distal end of the rotor rampedprojection 37. The stator ramped projection 27 and rotor rampedprojection 37 may be configured such that a radial stator/rotorclearance 23 exists between them, and such that this radial stator/rotorclearance 23 leads to an atypical stator/rotor clearance 25 a in theinboard direction. Generally, at least the ramped projection 27 (andadditionally in various aspects, the rotor ramped projection 37) may beoriented inboard with respect to the collection groove 26, but the scopeof the present disclosure is not so limited unless so indicated in thefollowing claims such that additional ramped projections 27 and/or rotorramped projections 37 may be employed.

It is contemplated that in an aspect of the shaft seal assembly 10 shownin FIG. 30, an interaction between the ramped projection 27 and rotorramped projection 37 may provide a unitizing function to the shaft sealassembly 10, such that a sealing ring 19 may be omitted from a shaftseal assembly 10 so configured. It is contemplated that for a desiredperformance level, it may be required that the most-outboard locatedradial stator/rotor clearance 23 and/or the radial stator/rotorclearance 23 on either side of the collection groove 26 be formed asclose clearance gap seals, as previously discussed above, and that therelative dimensions of those radial stator/rotor clearances 23 bemaintained as much as possible during operation. Accordingly, in certainapplications, axial shaft 14 movement in the inboard direction may causean increase in the axial dimension of one or more of the radialstator/rotor clearances 23, which may in turn decrease the effectivenessof the entire shaft seal assembly 10. Such axial shaft 14 movement mayoccur as a result of thermal growth, shaft 14 loading, or axial shaft 14movement may be an essential required feature of the rotating equipmenton which the shaft seal assembly 10 is installed, though other causesmay result in axial shaft 14 movement.

To prevent or mitigate the negative effects of axial shaft 14 movement,it may be desirable to configure the rotor 30 and/or stator 20 such thatthe relative axial positions therebetween are secure or relativelysecure. In an aspect, this may be accomplished via a ramped projection27 formed in the stator 20 having a ramp surface 27 a on the distal endthereof and a rotor ramped projection 37 formed in the rotor 30 having arotor ramp surface 37 a on the distal end thereof. The ramp surface 27 aand rotor ramp surface 37 a may be configured such that they aregenerally parallel with respect to one another, and such that the anglethereof may allow the rotor 30 to be inserted into the stator 20 bymoving the rotor 30 in a generally outboard direction with respect tothe stator. The ramp surface 27 a and rotor ramp surface 37 a may beangled such that when an axial force is applied to the rotor 30 in anoutboard direction, the stator 20 may be deformed momentarily as theramp surface 27 a and rotor ramp surface 37 a interact with one anotherso as to allow the rotor 30 to be properly positioned within the stator20 and with properly dimensioned and positioned radial stator/rotorclearance(s) 23. During this insertion process, it is contemplated thatit may be essential that the deformation of the stator 20 be within theelastic limits of the material comprising the stator 20 so that once therotor 30 is in proper position the stator 20 will return to itsessentially original size and shape.

It is contemplated that the ramp surface 27 a may be angled radiallyinward in the inboard-to-outboard direction, and that the rotor rampsurface 37 a may be angled radially inward in the inboard-to-outboarddirection though the scope of the shaft seal assembly 10 is not solimited unless indicated in the following claims. Further, it iscontemplated that the ramp surface 27 a and rotor ramp surface 37 a maybe generally parallel, though the scope of the shaft seal assembly 10 isnot so limited unless indicated in the following claims.

Once the rotor 30 is properly positioned with respect to the stator 20and the stator 20 generally returns to its original size and shape, theclose clearance gap seals of the radial stator/rotor clearance(s) 23 maybe maintained by the formation of a relatively small radial stator/rotorclearance 23 adjacent the overlapping axial surfaces between the largestdiameter of the rotor ramped projection 37 and the smallest diameter ofthe ramped projection 20. This overlap may prevent shaft 14 movement ina generally inboard direction from separating the rotor 30 from thestator 20, which may compromise the effectiveness of the close clearancegap seals formed at a radial stator/rotor clearance(s) 23.

Generally, it may be desirable for the shaft seal assembly 10 to beconfigured such that if the rotor 30 experiences a force in a generallyinboard direction (which may be caused by axial movement of the shaft 14in a generally inboard direction), the shaft 14 may slide axially withrespect to the rotor 30, and the overlapping ramp surface 27 a and rotorramp surface 37 a may serve to retain the rotor 30 in the properposition relative to the stator 20. Axial movement of the shaft 14 withrespect to the rotor 30 may require slippage at the drive ring 16 orother structure and/or method used to engage the rotor 30 with the shaft14. Accordingly, it is contemplated that it may be advantageous toprovide a sufficient amount of overlap at the ramp surface 27 a androtor ramp surface 37 a such that the integrity of the overlap willprevent separation of the stator 20 and rotor 30 while the shaft 14 isslid through the rotor 30 in a generally inboard direction. In an aspectthe amount of overlap may be between 0.1 and 1.0 inches withoutlimitation unless so indicated in the following claims. Generally, it iscontemplated that an optimal operating condition may be when the rotor30 turns freely inside the stator 20 in such a manner that forcedcontact between the rotor 30 and stator 20 at any radial stator/rotorclearance 23 and/or any axial stator/rotor clearance 25 is mitigatedand/or prevented.

It is contemplated that optimal functioning of a shaft seal assembly 10such as those shown in FIGS. 28-30 may require the axial dimension ofthe most-outboard radial stator/rotor clearance 23 be less than theaxial dimension of the radial stator/rotor clearance 23 adjacentoutboard wall 28 b of the collection groove 26. If the shaft sealassembly 10 is subjected to axial shaft 14 movement in a generallyoutboard direction during operation, the axial dimension of the radialstator/rotor clearances described immediately above may be reducedand/or eliminated, which may cause frictional dynamic contact betweenthe adjacent surfaces of the stator 20 and rotor 30. This frictionaldynamic contact may result in undesired heat generation, or the frictionbetween the static and dynamic surfaces may be sufficient to overcomethe friction between the drive ring 16 and shaft 14 and/or frictionbetween the drive ring 16 and rotor 30. Any of these scenarios couldresult in failure of the shaft seal assembly 10. Accordingly,maintaining a closer clearance at radial stator/rotor clearances 23described immediately above reduces the surface area that may besubjected to dynamic contact, which may result in less friction and/orheat generation upon contact, which may lower the likelihood of failure.

The materials used to construct the shaft seal assemblies 10, 25, 100,200, 202 and various elements thereof will vary depending on thespecific application, but it is contemplated that bronze, brass,stainless steel, or other non-sparking metals and/or metallic alloysand/or combinations thereof may be especially useful for someapplications. Accordingly, the above-referenced elements may beconstructed of any material known to those skilled in the art or laterdeveloped, which material is appropriate for the specific application ofthe shaft seal assembly, without departing from the spirit and scope ofthe shaft seal assemblies 25, 100, 200, 202 as disclosed and claimedherein. Further, the drive ring 16, O-ring 18, and/or sealing ring 19may be constructed of any material suitable for the specific applicationof the shaft seal assembly 10, which material includes but is notlimited to polymers, synthetic materials, elastomers, natural materials,and/or combinations thereof without limitation unless so indicated inthe following claims.

Having described the preferred embodiments, other features of the shaftseal assemblies disclosed herein will undoubtedly occur to those versedin the art, as will numerous modifications and alterations in theembodiments as illustrated herein, all of which may be achieved withoutdeparting from the spirit and scope of the shaft seal assembliesdisclosed herein. Accordingly, the methods and embodiments pictured anddescribed herein are for illustrative purposes only, and the scope ofthe present disclosure extends to all method and/or structures forproviding the various benefits and/or features of the shaft sealassemblies unless so indicated in the following claims. Furthermore, themethods and embodiments pictured and described herein are no waylimiting to the scope of the shoe covering 10 unless so stated in thefollowing claims.

It is understood that the shaft seal assemblies as disclosed hereinextends to all alternative combinations of one or more of the individualfeatures mentioned, evident from the text and/or drawings, and/orinherently disclosed. All of these different combinations constitutevarious alternative aspects of the shaft seal assemblies and/orcomponents thereof. The embodiments described herein explain the bestmodes known for practicing the shaft seal assemblies and/or componentsthereof and will enable others skilled in the art to utilize the same.The claims are to be construed to include alternative embodiments to theextent permitted by the prior art.

While the shaft seal assemblies have been described in connection withpreferred embodiments and specific examples, it is not intended that thescope be limited to the particular embodiments set forth, as theembodiments herein are intended in all respects to be illustrativerather than restrictive.

Unless otherwise expressly stated, it is in no way intended that anymethod set forth herein be construed as requiring that its steps beperformed in a specific order. Accordingly, where a method claim doesnot actually recite an order to be followed by its steps or it is nototherwise specifically stated in the claims or descriptions that thesteps are to be limited to a specific order, it is no way intended thatan order be inferred, in any respect. This holds for any possiblenon-express basis for interpretation, including but not limited to:matters of logic with respect to arrangement of steps or operationalflow; plain meaning derived from grammatical organization orpunctuation; the number or type of embodiments described in thespecification.

It will be apparent to those skilled in the art that variousmodifications and variations can be made without departing from thescope or spirit. Other embodiments will be apparent to those skilled inthe art from consideration of the specification and practice disclosedherein. It is intended that the specification and examples be consideredas illustrative only, with a true scope and spirit being indicated bythe following claims.

What is claimed is:
 1. A shaft seal assembly comprising: a. a statorconfigured to engage a housing, said stator comprising: i. a stator mainbody; ii. a stator inward radial projection extending radially inwardfrom said stator main body, wherein a distal end of said stator inwardradial projection is configured to provide a stator/shaft clearancebetween said distal end of said stator inward radial projection and ashaft extending from said housing; iii. a collection groove adjacentsaid stator inward radial projection, wherein an inboard side of saidstator inward radial projection forms an outboard wall of saidcollection groove; iv. a ramped projection adjacent said collectiongroove, wherein an outboard surface of said ramped projection forms aninboard wall of said collection groove, and wherein a ramp surface isformed on a distal end of said ramped projection; b. a rotor positionedwithin said stator, said rotor configured to engage said shaft, saidrotor comprising: i. a rotor main body; ii. a rotor axial projectionextending from said rotor main body, wherein said rotor axial projectionis positioned adjacent said distal end of said stator inward radialprojection, wherein no surfaces of said rotor are directly exposed to anexternal environment; and, iii. a rotor ramped projection extending fromsaid rotor main body, wherein a rotor ramp surface is formed on a distalend of said rotor ramped projection.
 2. The shaft seal assemblyaccording to claim 1 wherein said stator further comprises an annularrecess formed on said distal end of said inward radial projection. 3.The shaft seal assembly according to claim 2 wherein said annular recesscooperates with said rotor axial projection to form a first radialstator/rotor clearance and an axial stator/rotor clearance between saidstator and said rotor.
 4. The shaft seal assembly according to claim 3wherein said annular recess and said rotor axial projection are furtherdefined as cooperating to form a second radial stator/rotor clearancebetween said stator and said rotor.
 5. The shaft seal assembly accordingto claim 4 wherein said stator further comprises a barrier extendingradially outward from said stator main body.
 6. The shaft seal assemblyaccording to claim 5 wherein said stator further comprises a shoulderextending radially outward from said stator main body.
 7. The shaft sealassembly according to claim 6 wherein said stator further comprises anexterior groove positioned between said shoulder and said barrier. 8.The shaft seal assembly according to claim 7 wherein said stator furthercomprises a drain in fluid communication with said collection groove. 9.The shaft seal assembly according to claim 8 wherein said stator furthercomprises a stator sealing ring groove formed in said stator main body.10. The shaft seal assembly according to claim 9 wherein said rotorfurther comprises a rotor sealing ring groove formed in said rotor mainbody, and wherein said shaft seal assembly further comprises a sealingring, wherein a first portion of said sealing ring is positioned in saidstator sealing ring groove, and wherein a second portion of said sealingring is positioned in said rotor sealing ring groove.
 11. The shaft sealassembly according to claim 10 wherein an axial dimension of said statorsealing ring groove is defined as being approximately equal to an axialdimension of said rotor sealing ring groove, and wherein across-sectional dimension of said sealing ring groove is smaller thansaid axial dimension of said stator sealing ring groove.
 12. The shaftseal assembly according to claim 11 wherein a radial dimension of saidstator sealing ring groove is defined as being greater than a radialdimension of said rotor sealing ring groove, and wherein said radialdimension of said rotor sealing ring groove is greater than said axialdimension thereof.
 13. The shaft seal assembly according to claim 1wherein a width of said collection groove in an axial dimension isapproximately 46% of an overall length of said shaft seal assembly insaid axial dimension.
 14. The shaft seal assembly according to claim 14wherein a depth of said collection groove in a radial dimension isapproximately 40% of said overall length of said shaft seal assembly insaid axial dimension.
 15. The shaft seal assembly according to claim 1wherein a radially distal point of said ramp surface and a radial distalpoint of said rotor ramp surface overlap by at least 0.1 inches in theradial dimension.
 16. A method comprising: a. engaging a stator with ahousing, wherein said stator comprises: i. a stator main body; ii. astator inward radial projection extending radially inward from saidstator main body, wherein a distal end of said stator inward radialprojection is configured to provide a stator/shaft clearance betweensaid distal end of said stator inward radial projection and a shaftextending from said housing; iii. a collection groove adjacent saidstator inward radial projection, wherein an inboard side of said statorinward radial projection forms an outboard wall of said collectiongroove; iv. a ramped projection adjacent said collection groove, whereinan outboard surface of said ramped projection forms an inboard wall ofsaid collection groove, and wherein a ramp surface is formed on a distalend of said ramped projection; b. engaging a rotor with said shaftextending from and rotatable with respect to said housing, said rotorcomprising: i. a rotor main body; ii. a rotor axial projection extendingfrom said rotor main body, wherein said rotor axial projection ispositioned adjacent said distal end of said stator inward radialprojection, wherein no surfaces of said rotor are directly exposed to anexternal environment; iii. a rotor ramped projection extending from saidrotor main body, wherein a rotor ramp surface is formed on a distal endof said rotor ramped projection; c. collecting a contaminant in saidcollection groove; and, d. allowing said contaminant to exit said shaftseal assembly via a drain in fluid communication with said collectiongroove.
 17. A method of installing a shaft seal assembly, said methodcomprising: a. pressing a rotor into a stator, wherein said statorcomprises: i. a stator main body; ii. a stator inward radial projectionextending radially inward from said stator main body, wherein a distalend of said stator inward radial projection is configured to provide astator/shaft clearance between said distal end of said stator inwardradial projection and a shaft extending from said housing; and, iii. acollection groove adjacent said stator inward radial projection, whereinan inboard side of said stator inward radial projection forms anoutboard wall of said collection groove; iv. a ramped projectionadjacent said collection groove, wherein an outboard surface of saidramped projection forms an inboard wall of said collection groove, andwherein a ramp surface is formed on a distal end of said rampedprojection; b. wherein said rotor comprises: i. a rotor main body; ii. arotor axial projection extending from said rotor main body, wherein saidrotor axial projection is positioned adjacent said distal end of saidstator inward radial projection, wherein no surfaces of said rotor aredirectly exposed to an external environment; iii. a rotor rampedprojection extending from said rotor main body, wherein a rotor rampsurface is formed on a distal end of said rotor ramped projection,wherein pressing said rotor into said stator temporarily deforms saidstator as said ramp surface engages said rotor ramp surface; c.positioning said shaft seal assembly concentrically around a shaft; andd. moving said shaft seal assembly axially inward along said shafttoward a housing, wherein said shaft protrudes from said housing and isrotatable with respect thereto.
 18. The shaft seal assembly according toclaim 17 wherein a radially distal point of said ramp surface and aradial distal point of said rotor ramp surface overlap by at least 0.1inches in the radial dimension.
 19. The shaft seal assembly according toclaim 17 wherein said stator/shaft clearance is further defined asforming a close gap seal clearance between said distal end of saidstator inward radial projection and said shaft.
 20. The shaft sealassembly according to claim 17 wherein said rotor is entirely positionedinboard with respect to said stator inward radial projection.